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1/*
2 * Kprobes-based tracing events
3 *
4 * Created by Masami Hiramatsu <mhiramat@redhat.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 */
19
20#include <linux/module.h>
21#include <linux/uaccess.h>
22
23#include "trace_probe.h"
24
25#define KPROBE_EVENT_SYSTEM "kprobes"
26
27/**
28 * Kprobe event core functions
29 */
30struct trace_kprobe {
31 struct list_head list;
32 struct kretprobe rp; /* Use rp.kp for kprobe use */
33 unsigned long __percpu *nhit;
34 const char *symbol; /* symbol name */
35 struct trace_probe tp;
36};
37
38#define SIZEOF_TRACE_KPROBE(n) \
39 (offsetof(struct trace_kprobe, tp.args) + \
40 (sizeof(struct probe_arg) * (n)))
41
42
43static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
44{
45 return tk->rp.handler != NULL;
46}
47
48static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk)
49{
50 return tk->symbol ? tk->symbol : "unknown";
51}
52
53static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk)
54{
55 return tk->rp.kp.offset;
56}
57
58static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk)
59{
60 return !!(kprobe_gone(&tk->rp.kp));
61}
62
63static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk,
64 struct module *mod)
65{
66 int len = strlen(mod->name);
67 const char *name = trace_kprobe_symbol(tk);
68 return strncmp(mod->name, name, len) == 0 && name[len] == ':';
69}
70
71static nokprobe_inline bool trace_kprobe_is_on_module(struct trace_kprobe *tk)
72{
73 return !!strchr(trace_kprobe_symbol(tk), ':');
74}
75
76static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk)
77{
78 unsigned long nhit = 0;
79 int cpu;
80
81 for_each_possible_cpu(cpu)
82 nhit += *per_cpu_ptr(tk->nhit, cpu);
83
84 return nhit;
85}
86
87static int register_kprobe_event(struct trace_kprobe *tk);
88static int unregister_kprobe_event(struct trace_kprobe *tk);
89
90static DEFINE_MUTEX(probe_lock);
91static LIST_HEAD(probe_list);
92
93static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
94static int kretprobe_dispatcher(struct kretprobe_instance *ri,
95 struct pt_regs *regs);
96
97/* Memory fetching by symbol */
98struct symbol_cache {
99 char *symbol;
100 long offset;
101 unsigned long addr;
102};
103
104unsigned long update_symbol_cache(struct symbol_cache *sc)
105{
106 sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
107
108 if (sc->addr)
109 sc->addr += sc->offset;
110
111 return sc->addr;
112}
113
114void free_symbol_cache(struct symbol_cache *sc)
115{
116 kfree(sc->symbol);
117 kfree(sc);
118}
119
120struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
121{
122 struct symbol_cache *sc;
123
124 if (!sym || strlen(sym) == 0)
125 return NULL;
126
127 sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
128 if (!sc)
129 return NULL;
130
131 sc->symbol = kstrdup(sym, GFP_KERNEL);
132 if (!sc->symbol) {
133 kfree(sc);
134 return NULL;
135 }
136 sc->offset = offset;
137 update_symbol_cache(sc);
138
139 return sc;
140}
141
142/*
143 * Kprobes-specific fetch functions
144 */
145#define DEFINE_FETCH_stack(type) \
146static void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs, \
147 void *offset, void *dest) \
148{ \
149 *(type *)dest = (type)regs_get_kernel_stack_nth(regs, \
150 (unsigned int)((unsigned long)offset)); \
151} \
152NOKPROBE_SYMBOL(FETCH_FUNC_NAME(stack, type));
153
154DEFINE_BASIC_FETCH_FUNCS(stack)
155/* No string on the stack entry */
156#define fetch_stack_string NULL
157#define fetch_stack_string_size NULL
158
159#define DEFINE_FETCH_memory(type) \
160static void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs, \
161 void *addr, void *dest) \
162{ \
163 type retval; \
164 if (probe_kernel_address(addr, retval)) \
165 *(type *)dest = 0; \
166 else \
167 *(type *)dest = retval; \
168} \
169NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, type));
170
171DEFINE_BASIC_FETCH_FUNCS(memory)
172/*
173 * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
174 * length and relative data location.
175 */
176static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
177 void *addr, void *dest)
178{
179 int maxlen = get_rloc_len(*(u32 *)dest);
180 u8 *dst = get_rloc_data(dest);
181 long ret;
182
183 if (!maxlen)
184 return;
185
186 /*
187 * Try to get string again, since the string can be changed while
188 * probing.
189 */
190 ret = strncpy_from_unsafe(dst, addr, maxlen);
191
192 if (ret < 0) { /* Failed to fetch string */
193 dst[0] = '\0';
194 *(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest));
195 } else {
196 *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(*(u32 *)dest));
197 }
198}
199NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string));
200
201/* Return the length of string -- including null terminal byte */
202static void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
203 void *addr, void *dest)
204{
205 mm_segment_t old_fs;
206 int ret, len = 0;
207 u8 c;
208
209 old_fs = get_fs();
210 set_fs(KERNEL_DS);
211 pagefault_disable();
212
213 do {
214 ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1);
215 len++;
216 } while (c && ret == 0 && len < MAX_STRING_SIZE);
217
218 pagefault_enable();
219 set_fs(old_fs);
220
221 if (ret < 0) /* Failed to check the length */
222 *(u32 *)dest = 0;
223 else
224 *(u32 *)dest = len;
225}
226NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string_size));
227
228#define DEFINE_FETCH_symbol(type) \
229void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs, void *data, void *dest)\
230{ \
231 struct symbol_cache *sc = data; \
232 if (sc->addr) \
233 fetch_memory_##type(regs, (void *)sc->addr, dest); \
234 else \
235 *(type *)dest = 0; \
236} \
237NOKPROBE_SYMBOL(FETCH_FUNC_NAME(symbol, type));
238
239DEFINE_BASIC_FETCH_FUNCS(symbol)
240DEFINE_FETCH_symbol(string)
241DEFINE_FETCH_symbol(string_size)
242
243/* kprobes don't support file_offset fetch methods */
244#define fetch_file_offset_u8 NULL
245#define fetch_file_offset_u16 NULL
246#define fetch_file_offset_u32 NULL
247#define fetch_file_offset_u64 NULL
248#define fetch_file_offset_string NULL
249#define fetch_file_offset_string_size NULL
250
251/* Fetch type information table */
252static const struct fetch_type kprobes_fetch_type_table[] = {
253 /* Special types */
254 [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
255 sizeof(u32), 1, "__data_loc char[]"),
256 [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
257 string_size, sizeof(u32), 0, "u32"),
258 /* Basic types */
259 ASSIGN_FETCH_TYPE(u8, u8, 0),
260 ASSIGN_FETCH_TYPE(u16, u16, 0),
261 ASSIGN_FETCH_TYPE(u32, u32, 0),
262 ASSIGN_FETCH_TYPE(u64, u64, 0),
263 ASSIGN_FETCH_TYPE(s8, u8, 1),
264 ASSIGN_FETCH_TYPE(s16, u16, 1),
265 ASSIGN_FETCH_TYPE(s32, u32, 1),
266 ASSIGN_FETCH_TYPE(s64, u64, 1),
267 ASSIGN_FETCH_TYPE_ALIAS(x8, u8, u8, 0),
268 ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
269 ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
270 ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
271
272 ASSIGN_FETCH_TYPE_END
273};
274
275/*
276 * Allocate new trace_probe and initialize it (including kprobes).
277 */
278static struct trace_kprobe *alloc_trace_kprobe(const char *group,
279 const char *event,
280 void *addr,
281 const char *symbol,
282 unsigned long offs,
283 int nargs, bool is_return)
284{
285 struct trace_kprobe *tk;
286 int ret = -ENOMEM;
287
288 tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL);
289 if (!tk)
290 return ERR_PTR(ret);
291
292 tk->nhit = alloc_percpu(unsigned long);
293 if (!tk->nhit)
294 goto error;
295
296 if (symbol) {
297 tk->symbol = kstrdup(symbol, GFP_KERNEL);
298 if (!tk->symbol)
299 goto error;
300 tk->rp.kp.symbol_name = tk->symbol;
301 tk->rp.kp.offset = offs;
302 } else
303 tk->rp.kp.addr = addr;
304
305 if (is_return)
306 tk->rp.handler = kretprobe_dispatcher;
307 else
308 tk->rp.kp.pre_handler = kprobe_dispatcher;
309
310 if (!event || !is_good_name(event)) {
311 ret = -EINVAL;
312 goto error;
313 }
314
315 tk->tp.call.class = &tk->tp.class;
316 tk->tp.call.name = kstrdup(event, GFP_KERNEL);
317 if (!tk->tp.call.name)
318 goto error;
319
320 if (!group || !is_good_name(group)) {
321 ret = -EINVAL;
322 goto error;
323 }
324
325 tk->tp.class.system = kstrdup(group, GFP_KERNEL);
326 if (!tk->tp.class.system)
327 goto error;
328
329 INIT_LIST_HEAD(&tk->list);
330 INIT_LIST_HEAD(&tk->tp.files);
331 return tk;
332error:
333 kfree(tk->tp.call.name);
334 kfree(tk->symbol);
335 free_percpu(tk->nhit);
336 kfree(tk);
337 return ERR_PTR(ret);
338}
339
340static void free_trace_kprobe(struct trace_kprobe *tk)
341{
342 int i;
343
344 for (i = 0; i < tk->tp.nr_args; i++)
345 traceprobe_free_probe_arg(&tk->tp.args[i]);
346
347 kfree(tk->tp.call.class->system);
348 kfree(tk->tp.call.name);
349 kfree(tk->symbol);
350 free_percpu(tk->nhit);
351 kfree(tk);
352}
353
354static struct trace_kprobe *find_trace_kprobe(const char *event,
355 const char *group)
356{
357 struct trace_kprobe *tk;
358
359 list_for_each_entry(tk, &probe_list, list)
360 if (strcmp(trace_event_name(&tk->tp.call), event) == 0 &&
361 strcmp(tk->tp.call.class->system, group) == 0)
362 return tk;
363 return NULL;
364}
365
366/*
367 * Enable trace_probe
368 * if the file is NULL, enable "perf" handler, or enable "trace" handler.
369 */
370static int
371enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
372{
373 int ret = 0;
374
375 if (file) {
376 struct event_file_link *link;
377
378 link = kmalloc(sizeof(*link), GFP_KERNEL);
379 if (!link) {
380 ret = -ENOMEM;
381 goto out;
382 }
383
384 link->file = file;
385 list_add_tail_rcu(&link->list, &tk->tp.files);
386
387 tk->tp.flags |= TP_FLAG_TRACE;
388 } else
389 tk->tp.flags |= TP_FLAG_PROFILE;
390
391 if (trace_probe_is_registered(&tk->tp) && !trace_kprobe_has_gone(tk)) {
392 if (trace_kprobe_is_return(tk))
393 ret = enable_kretprobe(&tk->rp);
394 else
395 ret = enable_kprobe(&tk->rp.kp);
396 }
397 out:
398 return ret;
399}
400
401/*
402 * Disable trace_probe
403 * if the file is NULL, disable "perf" handler, or disable "trace" handler.
404 */
405static int
406disable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
407{
408 struct event_file_link *link = NULL;
409 int wait = 0;
410 int ret = 0;
411
412 if (file) {
413 link = find_event_file_link(&tk->tp, file);
414 if (!link) {
415 ret = -EINVAL;
416 goto out;
417 }
418
419 list_del_rcu(&link->list);
420 wait = 1;
421 if (!list_empty(&tk->tp.files))
422 goto out;
423
424 tk->tp.flags &= ~TP_FLAG_TRACE;
425 } else
426 tk->tp.flags &= ~TP_FLAG_PROFILE;
427
428 if (!trace_probe_is_enabled(&tk->tp) && trace_probe_is_registered(&tk->tp)) {
429 if (trace_kprobe_is_return(tk))
430 disable_kretprobe(&tk->rp);
431 else
432 disable_kprobe(&tk->rp.kp);
433 wait = 1;
434 }
435 out:
436 if (wait) {
437 /*
438 * Synchronize with kprobe_trace_func/kretprobe_trace_func
439 * to ensure disabled (all running handlers are finished).
440 * This is not only for kfree(), but also the caller,
441 * trace_remove_event_call() supposes it for releasing
442 * event_call related objects, which will be accessed in
443 * the kprobe_trace_func/kretprobe_trace_func.
444 */
445 synchronize_sched();
446 kfree(link); /* Ignored if link == NULL */
447 }
448
449 return ret;
450}
451
452/* Internal register function - just handle k*probes and flags */
453static int __register_trace_kprobe(struct trace_kprobe *tk)
454{
455 int i, ret;
456
457 if (trace_probe_is_registered(&tk->tp))
458 return -EINVAL;
459
460 for (i = 0; i < tk->tp.nr_args; i++)
461 traceprobe_update_arg(&tk->tp.args[i]);
462
463 /* Set/clear disabled flag according to tp->flag */
464 if (trace_probe_is_enabled(&tk->tp))
465 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
466 else
467 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
468
469 if (trace_kprobe_is_return(tk))
470 ret = register_kretprobe(&tk->rp);
471 else
472 ret = register_kprobe(&tk->rp.kp);
473
474 if (ret == 0)
475 tk->tp.flags |= TP_FLAG_REGISTERED;
476 else {
477 pr_warn("Could not insert probe at %s+%lu: %d\n",
478 trace_kprobe_symbol(tk), trace_kprobe_offset(tk), ret);
479 if (ret == -ENOENT && trace_kprobe_is_on_module(tk)) {
480 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
481 ret = 0;
482 } else if (ret == -EILSEQ) {
483 pr_warn("Probing address(0x%p) is not an instruction boundary.\n",
484 tk->rp.kp.addr);
485 ret = -EINVAL;
486 }
487 }
488
489 return ret;
490}
491
492/* Internal unregister function - just handle k*probes and flags */
493static void __unregister_trace_kprobe(struct trace_kprobe *tk)
494{
495 if (trace_probe_is_registered(&tk->tp)) {
496 if (trace_kprobe_is_return(tk))
497 unregister_kretprobe(&tk->rp);
498 else
499 unregister_kprobe(&tk->rp.kp);
500 tk->tp.flags &= ~TP_FLAG_REGISTERED;
501 /* Cleanup kprobe for reuse */
502 if (tk->rp.kp.symbol_name)
503 tk->rp.kp.addr = NULL;
504 }
505}
506
507/* Unregister a trace_probe and probe_event: call with locking probe_lock */
508static int unregister_trace_kprobe(struct trace_kprobe *tk)
509{
510 /* Enabled event can not be unregistered */
511 if (trace_probe_is_enabled(&tk->tp))
512 return -EBUSY;
513
514 /* Will fail if probe is being used by ftrace or perf */
515 if (unregister_kprobe_event(tk))
516 return -EBUSY;
517
518 __unregister_trace_kprobe(tk);
519 list_del(&tk->list);
520
521 return 0;
522}
523
524/* Register a trace_probe and probe_event */
525static int register_trace_kprobe(struct trace_kprobe *tk)
526{
527 struct trace_kprobe *old_tk;
528 int ret;
529
530 mutex_lock(&probe_lock);
531
532 /* Delete old (same name) event if exist */
533 old_tk = find_trace_kprobe(trace_event_name(&tk->tp.call),
534 tk->tp.call.class->system);
535 if (old_tk) {
536 ret = unregister_trace_kprobe(old_tk);
537 if (ret < 0)
538 goto end;
539 free_trace_kprobe(old_tk);
540 }
541
542 /* Register new event */
543 ret = register_kprobe_event(tk);
544 if (ret) {
545 pr_warn("Failed to register probe event(%d)\n", ret);
546 goto end;
547 }
548
549 /* Register k*probe */
550 ret = __register_trace_kprobe(tk);
551 if (ret < 0)
552 unregister_kprobe_event(tk);
553 else
554 list_add_tail(&tk->list, &probe_list);
555
556end:
557 mutex_unlock(&probe_lock);
558 return ret;
559}
560
561/* Module notifier call back, checking event on the module */
562static int trace_kprobe_module_callback(struct notifier_block *nb,
563 unsigned long val, void *data)
564{
565 struct module *mod = data;
566 struct trace_kprobe *tk;
567 int ret;
568
569 if (val != MODULE_STATE_COMING)
570 return NOTIFY_DONE;
571
572 /* Update probes on coming module */
573 mutex_lock(&probe_lock);
574 list_for_each_entry(tk, &probe_list, list) {
575 if (trace_kprobe_within_module(tk, mod)) {
576 /* Don't need to check busy - this should have gone. */
577 __unregister_trace_kprobe(tk);
578 ret = __register_trace_kprobe(tk);
579 if (ret)
580 pr_warn("Failed to re-register probe %s on %s: %d\n",
581 trace_event_name(&tk->tp.call),
582 mod->name, ret);
583 }
584 }
585 mutex_unlock(&probe_lock);
586
587 return NOTIFY_DONE;
588}
589
590static struct notifier_block trace_kprobe_module_nb = {
591 .notifier_call = trace_kprobe_module_callback,
592 .priority = 1 /* Invoked after kprobe module callback */
593};
594
595static int create_trace_kprobe(int argc, char **argv)
596{
597 /*
598 * Argument syntax:
599 * - Add kprobe: p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
600 * - Add kretprobe: r[:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
601 * Fetch args:
602 * $retval : fetch return value
603 * $stack : fetch stack address
604 * $stackN : fetch Nth of stack (N:0-)
605 * $comm : fetch current task comm
606 * @ADDR : fetch memory at ADDR (ADDR should be in kernel)
607 * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
608 * %REG : fetch register REG
609 * Dereferencing memory fetch:
610 * +|-offs(ARG) : fetch memory at ARG +|- offs address.
611 * Alias name of args:
612 * NAME=FETCHARG : set NAME as alias of FETCHARG.
613 * Type of args:
614 * FETCHARG:TYPE : use TYPE instead of unsigned long.
615 */
616 struct trace_kprobe *tk;
617 int i, ret = 0;
618 bool is_return = false, is_delete = false;
619 char *symbol = NULL, *event = NULL, *group = NULL;
620 char *arg;
621 unsigned long offset = 0;
622 void *addr = NULL;
623 char buf[MAX_EVENT_NAME_LEN];
624
625 /* argc must be >= 1 */
626 if (argv[0][0] == 'p')
627 is_return = false;
628 else if (argv[0][0] == 'r')
629 is_return = true;
630 else if (argv[0][0] == '-')
631 is_delete = true;
632 else {
633 pr_info("Probe definition must be started with 'p', 'r' or"
634 " '-'.\n");
635 return -EINVAL;
636 }
637
638 if (argv[0][1] == ':') {
639 event = &argv[0][2];
640 if (strchr(event, '/')) {
641 group = event;
642 event = strchr(group, '/') + 1;
643 event[-1] = '\0';
644 if (strlen(group) == 0) {
645 pr_info("Group name is not specified\n");
646 return -EINVAL;
647 }
648 }
649 if (strlen(event) == 0) {
650 pr_info("Event name is not specified\n");
651 return -EINVAL;
652 }
653 }
654 if (!group)
655 group = KPROBE_EVENT_SYSTEM;
656
657 if (is_delete) {
658 if (!event) {
659 pr_info("Delete command needs an event name.\n");
660 return -EINVAL;
661 }
662 mutex_lock(&probe_lock);
663 tk = find_trace_kprobe(event, group);
664 if (!tk) {
665 mutex_unlock(&probe_lock);
666 pr_info("Event %s/%s doesn't exist.\n", group, event);
667 return -ENOENT;
668 }
669 /* delete an event */
670 ret = unregister_trace_kprobe(tk);
671 if (ret == 0)
672 free_trace_kprobe(tk);
673 mutex_unlock(&probe_lock);
674 return ret;
675 }
676
677 if (argc < 2) {
678 pr_info("Probe point is not specified.\n");
679 return -EINVAL;
680 }
681 if (isdigit(argv[1][0])) {
682 if (is_return) {
683 pr_info("Return probe point must be a symbol.\n");
684 return -EINVAL;
685 }
686 /* an address specified */
687 ret = kstrtoul(&argv[1][0], 0, (unsigned long *)&addr);
688 if (ret) {
689 pr_info("Failed to parse address.\n");
690 return ret;
691 }
692 } else {
693 /* a symbol specified */
694 symbol = argv[1];
695 /* TODO: support .init module functions */
696 ret = traceprobe_split_symbol_offset(symbol, &offset);
697 if (ret) {
698 pr_info("Failed to parse symbol.\n");
699 return ret;
700 }
701 if (offset && is_return) {
702 pr_info("Return probe must be used without offset.\n");
703 return -EINVAL;
704 }
705 }
706 argc -= 2; argv += 2;
707
708 /* setup a probe */
709 if (!event) {
710 /* Make a new event name */
711 if (symbol)
712 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
713 is_return ? 'r' : 'p', symbol, offset);
714 else
715 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
716 is_return ? 'r' : 'p', addr);
717 event = buf;
718 }
719 tk = alloc_trace_kprobe(group, event, addr, symbol, offset, argc,
720 is_return);
721 if (IS_ERR(tk)) {
722 pr_info("Failed to allocate trace_probe.(%d)\n",
723 (int)PTR_ERR(tk));
724 return PTR_ERR(tk);
725 }
726
727 /* parse arguments */
728 ret = 0;
729 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
730 struct probe_arg *parg = &tk->tp.args[i];
731
732 /* Increment count for freeing args in error case */
733 tk->tp.nr_args++;
734
735 /* Parse argument name */
736 arg = strchr(argv[i], '=');
737 if (arg) {
738 *arg++ = '\0';
739 parg->name = kstrdup(argv[i], GFP_KERNEL);
740 } else {
741 arg = argv[i];
742 /* If argument name is omitted, set "argN" */
743 snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
744 parg->name = kstrdup(buf, GFP_KERNEL);
745 }
746
747 if (!parg->name) {
748 pr_info("Failed to allocate argument[%d] name.\n", i);
749 ret = -ENOMEM;
750 goto error;
751 }
752
753 if (!is_good_name(parg->name)) {
754 pr_info("Invalid argument[%d] name: %s\n",
755 i, parg->name);
756 ret = -EINVAL;
757 goto error;
758 }
759
760 if (traceprobe_conflict_field_name(parg->name,
761 tk->tp.args, i)) {
762 pr_info("Argument[%d] name '%s' conflicts with "
763 "another field.\n", i, argv[i]);
764 ret = -EINVAL;
765 goto error;
766 }
767
768 /* Parse fetch argument */
769 ret = traceprobe_parse_probe_arg(arg, &tk->tp.size, parg,
770 is_return, true,
771 kprobes_fetch_type_table);
772 if (ret) {
773 pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
774 goto error;
775 }
776 }
777
778 ret = register_trace_kprobe(tk);
779 if (ret)
780 goto error;
781 return 0;
782
783error:
784 free_trace_kprobe(tk);
785 return ret;
786}
787
788static int release_all_trace_kprobes(void)
789{
790 struct trace_kprobe *tk;
791 int ret = 0;
792
793 mutex_lock(&probe_lock);
794 /* Ensure no probe is in use. */
795 list_for_each_entry(tk, &probe_list, list)
796 if (trace_probe_is_enabled(&tk->tp)) {
797 ret = -EBUSY;
798 goto end;
799 }
800 /* TODO: Use batch unregistration */
801 while (!list_empty(&probe_list)) {
802 tk = list_entry(probe_list.next, struct trace_kprobe, list);
803 ret = unregister_trace_kprobe(tk);
804 if (ret)
805 goto end;
806 free_trace_kprobe(tk);
807 }
808
809end:
810 mutex_unlock(&probe_lock);
811
812 return ret;
813}
814
815/* Probes listing interfaces */
816static void *probes_seq_start(struct seq_file *m, loff_t *pos)
817{
818 mutex_lock(&probe_lock);
819 return seq_list_start(&probe_list, *pos);
820}
821
822static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
823{
824 return seq_list_next(v, &probe_list, pos);
825}
826
827static void probes_seq_stop(struct seq_file *m, void *v)
828{
829 mutex_unlock(&probe_lock);
830}
831
832static int probes_seq_show(struct seq_file *m, void *v)
833{
834 struct trace_kprobe *tk = v;
835 int i;
836
837 seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
838 seq_printf(m, ":%s/%s", tk->tp.call.class->system,
839 trace_event_name(&tk->tp.call));
840
841 if (!tk->symbol)
842 seq_printf(m, " 0x%p", tk->rp.kp.addr);
843 else if (tk->rp.kp.offset)
844 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
845 tk->rp.kp.offset);
846 else
847 seq_printf(m, " %s", trace_kprobe_symbol(tk));
848
849 for (i = 0; i < tk->tp.nr_args; i++)
850 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
851 seq_putc(m, '\n');
852
853 return 0;
854}
855
856static const struct seq_operations probes_seq_op = {
857 .start = probes_seq_start,
858 .next = probes_seq_next,
859 .stop = probes_seq_stop,
860 .show = probes_seq_show
861};
862
863static int probes_open(struct inode *inode, struct file *file)
864{
865 int ret;
866
867 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
868 ret = release_all_trace_kprobes();
869 if (ret < 0)
870 return ret;
871 }
872
873 return seq_open(file, &probes_seq_op);
874}
875
876static ssize_t probes_write(struct file *file, const char __user *buffer,
877 size_t count, loff_t *ppos)
878{
879 return traceprobe_probes_write(file, buffer, count, ppos,
880 create_trace_kprobe);
881}
882
883static const struct file_operations kprobe_events_ops = {
884 .owner = THIS_MODULE,
885 .open = probes_open,
886 .read = seq_read,
887 .llseek = seq_lseek,
888 .release = seq_release,
889 .write = probes_write,
890};
891
892/* Probes profiling interfaces */
893static int probes_profile_seq_show(struct seq_file *m, void *v)
894{
895 struct trace_kprobe *tk = v;
896
897 seq_printf(m, " %-44s %15lu %15lu\n",
898 trace_event_name(&tk->tp.call),
899 trace_kprobe_nhit(tk),
900 tk->rp.kp.nmissed);
901
902 return 0;
903}
904
905static const struct seq_operations profile_seq_op = {
906 .start = probes_seq_start,
907 .next = probes_seq_next,
908 .stop = probes_seq_stop,
909 .show = probes_profile_seq_show
910};
911
912static int profile_open(struct inode *inode, struct file *file)
913{
914 return seq_open(file, &profile_seq_op);
915}
916
917static const struct file_operations kprobe_profile_ops = {
918 .owner = THIS_MODULE,
919 .open = profile_open,
920 .read = seq_read,
921 .llseek = seq_lseek,
922 .release = seq_release,
923};
924
925/* Kprobe handler */
926static nokprobe_inline void
927__kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
928 struct trace_event_file *trace_file)
929{
930 struct kprobe_trace_entry_head *entry;
931 struct ring_buffer_event *event;
932 struct ring_buffer *buffer;
933 int size, dsize, pc;
934 unsigned long irq_flags;
935 struct trace_event_call *call = &tk->tp.call;
936
937 WARN_ON(call != trace_file->event_call);
938
939 if (trace_trigger_soft_disabled(trace_file))
940 return;
941
942 local_save_flags(irq_flags);
943 pc = preempt_count();
944
945 dsize = __get_data_size(&tk->tp, regs);
946 size = sizeof(*entry) + tk->tp.size + dsize;
947
948 event = trace_event_buffer_lock_reserve(&buffer, trace_file,
949 call->event.type,
950 size, irq_flags, pc);
951 if (!event)
952 return;
953
954 entry = ring_buffer_event_data(event);
955 entry->ip = (unsigned long)tk->rp.kp.addr;
956 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
957
958 event_trigger_unlock_commit_regs(trace_file, buffer, event,
959 entry, irq_flags, pc, regs);
960}
961
962static void
963kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
964{
965 struct event_file_link *link;
966
967 list_for_each_entry_rcu(link, &tk->tp.files, list)
968 __kprobe_trace_func(tk, regs, link->file);
969}
970NOKPROBE_SYMBOL(kprobe_trace_func);
971
972/* Kretprobe handler */
973static nokprobe_inline void
974__kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
975 struct pt_regs *regs,
976 struct trace_event_file *trace_file)
977{
978 struct kretprobe_trace_entry_head *entry;
979 struct ring_buffer_event *event;
980 struct ring_buffer *buffer;
981 int size, pc, dsize;
982 unsigned long irq_flags;
983 struct trace_event_call *call = &tk->tp.call;
984
985 WARN_ON(call != trace_file->event_call);
986
987 if (trace_trigger_soft_disabled(trace_file))
988 return;
989
990 local_save_flags(irq_flags);
991 pc = preempt_count();
992
993 dsize = __get_data_size(&tk->tp, regs);
994 size = sizeof(*entry) + tk->tp.size + dsize;
995
996 event = trace_event_buffer_lock_reserve(&buffer, trace_file,
997 call->event.type,
998 size, irq_flags, pc);
999 if (!event)
1000 return;
1001
1002 entry = ring_buffer_event_data(event);
1003 entry->func = (unsigned long)tk->rp.kp.addr;
1004 entry->ret_ip = (unsigned long)ri->ret_addr;
1005 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1006
1007 event_trigger_unlock_commit_regs(trace_file, buffer, event,
1008 entry, irq_flags, pc, regs);
1009}
1010
1011static void
1012kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1013 struct pt_regs *regs)
1014{
1015 struct event_file_link *link;
1016
1017 list_for_each_entry_rcu(link, &tk->tp.files, list)
1018 __kretprobe_trace_func(tk, ri, regs, link->file);
1019}
1020NOKPROBE_SYMBOL(kretprobe_trace_func);
1021
1022/* Event entry printers */
1023static enum print_line_t
1024print_kprobe_event(struct trace_iterator *iter, int flags,
1025 struct trace_event *event)
1026{
1027 struct kprobe_trace_entry_head *field;
1028 struct trace_seq *s = &iter->seq;
1029 struct trace_probe *tp;
1030 u8 *data;
1031 int i;
1032
1033 field = (struct kprobe_trace_entry_head *)iter->ent;
1034 tp = container_of(event, struct trace_probe, call.event);
1035
1036 trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1037
1038 if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1039 goto out;
1040
1041 trace_seq_putc(s, ')');
1042
1043 data = (u8 *)&field[1];
1044 for (i = 0; i < tp->nr_args; i++)
1045 if (!tp->args[i].type->print(s, tp->args[i].name,
1046 data + tp->args[i].offset, field))
1047 goto out;
1048
1049 trace_seq_putc(s, '\n');
1050 out:
1051 return trace_handle_return(s);
1052}
1053
1054static enum print_line_t
1055print_kretprobe_event(struct trace_iterator *iter, int flags,
1056 struct trace_event *event)
1057{
1058 struct kretprobe_trace_entry_head *field;
1059 struct trace_seq *s = &iter->seq;
1060 struct trace_probe *tp;
1061 u8 *data;
1062 int i;
1063
1064 field = (struct kretprobe_trace_entry_head *)iter->ent;
1065 tp = container_of(event, struct trace_probe, call.event);
1066
1067 trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1068
1069 if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1070 goto out;
1071
1072 trace_seq_puts(s, " <- ");
1073
1074 if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1075 goto out;
1076
1077 trace_seq_putc(s, ')');
1078
1079 data = (u8 *)&field[1];
1080 for (i = 0; i < tp->nr_args; i++)
1081 if (!tp->args[i].type->print(s, tp->args[i].name,
1082 data + tp->args[i].offset, field))
1083 goto out;
1084
1085 trace_seq_putc(s, '\n');
1086
1087 out:
1088 return trace_handle_return(s);
1089}
1090
1091
1092static int kprobe_event_define_fields(struct trace_event_call *event_call)
1093{
1094 int ret, i;
1095 struct kprobe_trace_entry_head field;
1096 struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1097
1098 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1099 /* Set argument names as fields */
1100 for (i = 0; i < tk->tp.nr_args; i++) {
1101 struct probe_arg *parg = &tk->tp.args[i];
1102
1103 ret = trace_define_field(event_call, parg->type->fmttype,
1104 parg->name,
1105 sizeof(field) + parg->offset,
1106 parg->type->size,
1107 parg->type->is_signed,
1108 FILTER_OTHER);
1109 if (ret)
1110 return ret;
1111 }
1112 return 0;
1113}
1114
1115static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1116{
1117 int ret, i;
1118 struct kretprobe_trace_entry_head field;
1119 struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1120
1121 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1122 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1123 /* Set argument names as fields */
1124 for (i = 0; i < tk->tp.nr_args; i++) {
1125 struct probe_arg *parg = &tk->tp.args[i];
1126
1127 ret = trace_define_field(event_call, parg->type->fmttype,
1128 parg->name,
1129 sizeof(field) + parg->offset,
1130 parg->type->size,
1131 parg->type->is_signed,
1132 FILTER_OTHER);
1133 if (ret)
1134 return ret;
1135 }
1136 return 0;
1137}
1138
1139#ifdef CONFIG_PERF_EVENTS
1140
1141/* Kprobe profile handler */
1142static void
1143kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1144{
1145 struct trace_event_call *call = &tk->tp.call;
1146 struct bpf_prog *prog = call->prog;
1147 struct kprobe_trace_entry_head *entry;
1148 struct hlist_head *head;
1149 int size, __size, dsize;
1150 int rctx;
1151
1152 if (prog && !trace_call_bpf(prog, regs))
1153 return;
1154
1155 head = this_cpu_ptr(call->perf_events);
1156 if (hlist_empty(head))
1157 return;
1158
1159 dsize = __get_data_size(&tk->tp, regs);
1160 __size = sizeof(*entry) + tk->tp.size + dsize;
1161 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1162 size -= sizeof(u32);
1163
1164 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1165 if (!entry)
1166 return;
1167
1168 entry->ip = (unsigned long)tk->rp.kp.addr;
1169 memset(&entry[1], 0, dsize);
1170 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1171 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1172 head, NULL);
1173}
1174NOKPROBE_SYMBOL(kprobe_perf_func);
1175
1176/* Kretprobe profile handler */
1177static void
1178kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1179 struct pt_regs *regs)
1180{
1181 struct trace_event_call *call = &tk->tp.call;
1182 struct bpf_prog *prog = call->prog;
1183 struct kretprobe_trace_entry_head *entry;
1184 struct hlist_head *head;
1185 int size, __size, dsize;
1186 int rctx;
1187
1188 if (prog && !trace_call_bpf(prog, regs))
1189 return;
1190
1191 head = this_cpu_ptr(call->perf_events);
1192 if (hlist_empty(head))
1193 return;
1194
1195 dsize = __get_data_size(&tk->tp, regs);
1196 __size = sizeof(*entry) + tk->tp.size + dsize;
1197 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1198 size -= sizeof(u32);
1199
1200 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1201 if (!entry)
1202 return;
1203
1204 entry->func = (unsigned long)tk->rp.kp.addr;
1205 entry->ret_ip = (unsigned long)ri->ret_addr;
1206 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1207 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1208 head, NULL);
1209}
1210NOKPROBE_SYMBOL(kretprobe_perf_func);
1211#endif /* CONFIG_PERF_EVENTS */
1212
1213/*
1214 * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1215 *
1216 * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1217 * lockless, but we can't race with this __init function.
1218 */
1219static int kprobe_register(struct trace_event_call *event,
1220 enum trace_reg type, void *data)
1221{
1222 struct trace_kprobe *tk = (struct trace_kprobe *)event->data;
1223 struct trace_event_file *file = data;
1224
1225 switch (type) {
1226 case TRACE_REG_REGISTER:
1227 return enable_trace_kprobe(tk, file);
1228 case TRACE_REG_UNREGISTER:
1229 return disable_trace_kprobe(tk, file);
1230
1231#ifdef CONFIG_PERF_EVENTS
1232 case TRACE_REG_PERF_REGISTER:
1233 return enable_trace_kprobe(tk, NULL);
1234 case TRACE_REG_PERF_UNREGISTER:
1235 return disable_trace_kprobe(tk, NULL);
1236 case TRACE_REG_PERF_OPEN:
1237 case TRACE_REG_PERF_CLOSE:
1238 case TRACE_REG_PERF_ADD:
1239 case TRACE_REG_PERF_DEL:
1240 return 0;
1241#endif
1242 }
1243 return 0;
1244}
1245
1246static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1247{
1248 struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1249
1250 raw_cpu_inc(*tk->nhit);
1251
1252 if (tk->tp.flags & TP_FLAG_TRACE)
1253 kprobe_trace_func(tk, regs);
1254#ifdef CONFIG_PERF_EVENTS
1255 if (tk->tp.flags & TP_FLAG_PROFILE)
1256 kprobe_perf_func(tk, regs);
1257#endif
1258 return 0; /* We don't tweek kernel, so just return 0 */
1259}
1260NOKPROBE_SYMBOL(kprobe_dispatcher);
1261
1262static int
1263kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1264{
1265 struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp);
1266
1267 raw_cpu_inc(*tk->nhit);
1268
1269 if (tk->tp.flags & TP_FLAG_TRACE)
1270 kretprobe_trace_func(tk, ri, regs);
1271#ifdef CONFIG_PERF_EVENTS
1272 if (tk->tp.flags & TP_FLAG_PROFILE)
1273 kretprobe_perf_func(tk, ri, regs);
1274#endif
1275 return 0; /* We don't tweek kernel, so just return 0 */
1276}
1277NOKPROBE_SYMBOL(kretprobe_dispatcher);
1278
1279static struct trace_event_functions kretprobe_funcs = {
1280 .trace = print_kretprobe_event
1281};
1282
1283static struct trace_event_functions kprobe_funcs = {
1284 .trace = print_kprobe_event
1285};
1286
1287static int register_kprobe_event(struct trace_kprobe *tk)
1288{
1289 struct trace_event_call *call = &tk->tp.call;
1290 int ret;
1291
1292 /* Initialize trace_event_call */
1293 INIT_LIST_HEAD(&call->class->fields);
1294 if (trace_kprobe_is_return(tk)) {
1295 call->event.funcs = &kretprobe_funcs;
1296 call->class->define_fields = kretprobe_event_define_fields;
1297 } else {
1298 call->event.funcs = &kprobe_funcs;
1299 call->class->define_fields = kprobe_event_define_fields;
1300 }
1301 if (set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0)
1302 return -ENOMEM;
1303 ret = register_trace_event(&call->event);
1304 if (!ret) {
1305 kfree(call->print_fmt);
1306 return -ENODEV;
1307 }
1308 call->flags = TRACE_EVENT_FL_KPROBE;
1309 call->class->reg = kprobe_register;
1310 call->data = tk;
1311 ret = trace_add_event_call(call);
1312 if (ret) {
1313 pr_info("Failed to register kprobe event: %s\n",
1314 trace_event_name(call));
1315 kfree(call->print_fmt);
1316 unregister_trace_event(&call->event);
1317 }
1318 return ret;
1319}
1320
1321static int unregister_kprobe_event(struct trace_kprobe *tk)
1322{
1323 int ret;
1324
1325 /* tp->event is unregistered in trace_remove_event_call() */
1326 ret = trace_remove_event_call(&tk->tp.call);
1327 if (!ret)
1328 kfree(tk->tp.call.print_fmt);
1329 return ret;
1330}
1331
1332/* Make a tracefs interface for controlling probe points */
1333static __init int init_kprobe_trace(void)
1334{
1335 struct dentry *d_tracer;
1336 struct dentry *entry;
1337
1338 if (register_module_notifier(&trace_kprobe_module_nb))
1339 return -EINVAL;
1340
1341 d_tracer = tracing_init_dentry();
1342 if (IS_ERR(d_tracer))
1343 return 0;
1344
1345 entry = tracefs_create_file("kprobe_events", 0644, d_tracer,
1346 NULL, &kprobe_events_ops);
1347
1348 /* Event list interface */
1349 if (!entry)
1350 pr_warn("Could not create tracefs 'kprobe_events' entry\n");
1351
1352 /* Profile interface */
1353 entry = tracefs_create_file("kprobe_profile", 0444, d_tracer,
1354 NULL, &kprobe_profile_ops);
1355
1356 if (!entry)
1357 pr_warn("Could not create tracefs 'kprobe_profile' entry\n");
1358 return 0;
1359}
1360fs_initcall(init_kprobe_trace);
1361
1362
1363#ifdef CONFIG_FTRACE_STARTUP_TEST
1364/*
1365 * The "__used" keeps gcc from removing the function symbol
1366 * from the kallsyms table. 'noinline' makes sure that there
1367 * isn't an inlined version used by the test method below
1368 */
1369static __used __init noinline int
1370kprobe_trace_selftest_target(int a1, int a2, int a3, int a4, int a5, int a6)
1371{
1372 return a1 + a2 + a3 + a4 + a5 + a6;
1373}
1374
1375static __init struct trace_event_file *
1376find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1377{
1378 struct trace_event_file *file;
1379
1380 list_for_each_entry(file, &tr->events, list)
1381 if (file->event_call == &tk->tp.call)
1382 return file;
1383
1384 return NULL;
1385}
1386
1387/*
1388 * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1389 * stage, we can do this lockless.
1390 */
1391static __init int kprobe_trace_self_tests_init(void)
1392{
1393 int ret, warn = 0;
1394 int (*target)(int, int, int, int, int, int);
1395 struct trace_kprobe *tk;
1396 struct trace_event_file *file;
1397
1398 if (tracing_is_disabled())
1399 return -ENODEV;
1400
1401 target = kprobe_trace_selftest_target;
1402
1403 pr_info("Testing kprobe tracing: ");
1404
1405 ret = traceprobe_command("p:testprobe kprobe_trace_selftest_target "
1406 "$stack $stack0 +0($stack)",
1407 create_trace_kprobe);
1408 if (WARN_ON_ONCE(ret)) {
1409 pr_warn("error on probing function entry.\n");
1410 warn++;
1411 } else {
1412 /* Enable trace point */
1413 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1414 if (WARN_ON_ONCE(tk == NULL)) {
1415 pr_warn("error on getting new probe.\n");
1416 warn++;
1417 } else {
1418 file = find_trace_probe_file(tk, top_trace_array());
1419 if (WARN_ON_ONCE(file == NULL)) {
1420 pr_warn("error on getting probe file.\n");
1421 warn++;
1422 } else
1423 enable_trace_kprobe(tk, file);
1424 }
1425 }
1426
1427 ret = traceprobe_command("r:testprobe2 kprobe_trace_selftest_target "
1428 "$retval", create_trace_kprobe);
1429 if (WARN_ON_ONCE(ret)) {
1430 pr_warn("error on probing function return.\n");
1431 warn++;
1432 } else {
1433 /* Enable trace point */
1434 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1435 if (WARN_ON_ONCE(tk == NULL)) {
1436 pr_warn("error on getting 2nd new probe.\n");
1437 warn++;
1438 } else {
1439 file = find_trace_probe_file(tk, top_trace_array());
1440 if (WARN_ON_ONCE(file == NULL)) {
1441 pr_warn("error on getting probe file.\n");
1442 warn++;
1443 } else
1444 enable_trace_kprobe(tk, file);
1445 }
1446 }
1447
1448 if (warn)
1449 goto end;
1450
1451 ret = target(1, 2, 3, 4, 5, 6);
1452
1453 /*
1454 * Not expecting an error here, the check is only to prevent the
1455 * optimizer from removing the call to target() as otherwise there
1456 * are no side-effects and the call is never performed.
1457 */
1458 if (ret != 21)
1459 warn++;
1460
1461 /* Disable trace points before removing it */
1462 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1463 if (WARN_ON_ONCE(tk == NULL)) {
1464 pr_warn("error on getting test probe.\n");
1465 warn++;
1466 } else {
1467 if (trace_kprobe_nhit(tk) != 1) {
1468 pr_warn("incorrect number of testprobe hits\n");
1469 warn++;
1470 }
1471
1472 file = find_trace_probe_file(tk, top_trace_array());
1473 if (WARN_ON_ONCE(file == NULL)) {
1474 pr_warn("error on getting probe file.\n");
1475 warn++;
1476 } else
1477 disable_trace_kprobe(tk, file);
1478 }
1479
1480 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1481 if (WARN_ON_ONCE(tk == NULL)) {
1482 pr_warn("error on getting 2nd test probe.\n");
1483 warn++;
1484 } else {
1485 if (trace_kprobe_nhit(tk) != 1) {
1486 pr_warn("incorrect number of testprobe2 hits\n");
1487 warn++;
1488 }
1489
1490 file = find_trace_probe_file(tk, top_trace_array());
1491 if (WARN_ON_ONCE(file == NULL)) {
1492 pr_warn("error on getting probe file.\n");
1493 warn++;
1494 } else
1495 disable_trace_kprobe(tk, file);
1496 }
1497
1498 ret = traceprobe_command("-:testprobe", create_trace_kprobe);
1499 if (WARN_ON_ONCE(ret)) {
1500 pr_warn("error on deleting a probe.\n");
1501 warn++;
1502 }
1503
1504 ret = traceprobe_command("-:testprobe2", create_trace_kprobe);
1505 if (WARN_ON_ONCE(ret)) {
1506 pr_warn("error on deleting a probe.\n");
1507 warn++;
1508 }
1509
1510end:
1511 release_all_trace_kprobes();
1512 if (warn)
1513 pr_cont("NG: Some tests are failed. Please check them.\n");
1514 else
1515 pr_cont("OK\n");
1516 return 0;
1517}
1518
1519late_initcall(kprobe_trace_self_tests_init);
1520
1521#endif
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Kprobes-based tracing events
4 *
5 * Created by Masami Hiramatsu <mhiramat@redhat.com>
6 *
7 */
8#define pr_fmt(fmt) "trace_kprobe: " fmt
9
10#include <linux/security.h>
11#include <linux/module.h>
12#include <linux/uaccess.h>
13#include <linux/rculist.h>
14#include <linux/error-injection.h>
15
16#include <asm/setup.h> /* for COMMAND_LINE_SIZE */
17
18#include "trace_dynevent.h"
19#include "trace_kprobe_selftest.h"
20#include "trace_probe.h"
21#include "trace_probe_tmpl.h"
22
23#define KPROBE_EVENT_SYSTEM "kprobes"
24#define KRETPROBE_MAXACTIVE_MAX 4096
25#define MAX_KPROBE_CMDLINE_SIZE 1024
26
27/* Kprobe early definition from command line */
28static char kprobe_boot_events_buf[COMMAND_LINE_SIZE] __initdata;
29static bool kprobe_boot_events_enabled __initdata;
30
31static int __init set_kprobe_boot_events(char *str)
32{
33 strlcpy(kprobe_boot_events_buf, str, COMMAND_LINE_SIZE);
34 return 0;
35}
36__setup("kprobe_event=", set_kprobe_boot_events);
37
38static int trace_kprobe_create(int argc, const char **argv);
39static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev);
40static int trace_kprobe_release(struct dyn_event *ev);
41static bool trace_kprobe_is_busy(struct dyn_event *ev);
42static bool trace_kprobe_match(const char *system, const char *event,
43 int argc, const char **argv, struct dyn_event *ev);
44
45static struct dyn_event_operations trace_kprobe_ops = {
46 .create = trace_kprobe_create,
47 .show = trace_kprobe_show,
48 .is_busy = trace_kprobe_is_busy,
49 .free = trace_kprobe_release,
50 .match = trace_kprobe_match,
51};
52
53/*
54 * Kprobe event core functions
55 */
56struct trace_kprobe {
57 struct dyn_event devent;
58 struct kretprobe rp; /* Use rp.kp for kprobe use */
59 unsigned long __percpu *nhit;
60 const char *symbol; /* symbol name */
61 struct trace_probe tp;
62};
63
64static bool is_trace_kprobe(struct dyn_event *ev)
65{
66 return ev->ops == &trace_kprobe_ops;
67}
68
69static struct trace_kprobe *to_trace_kprobe(struct dyn_event *ev)
70{
71 return container_of(ev, struct trace_kprobe, devent);
72}
73
74/**
75 * for_each_trace_kprobe - iterate over the trace_kprobe list
76 * @pos: the struct trace_kprobe * for each entry
77 * @dpos: the struct dyn_event * to use as a loop cursor
78 */
79#define for_each_trace_kprobe(pos, dpos) \
80 for_each_dyn_event(dpos) \
81 if (is_trace_kprobe(dpos) && (pos = to_trace_kprobe(dpos)))
82
83#define SIZEOF_TRACE_KPROBE(n) \
84 (offsetof(struct trace_kprobe, tp.args) + \
85 (sizeof(struct probe_arg) * (n)))
86
87static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
88{
89 return tk->rp.handler != NULL;
90}
91
92static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk)
93{
94 return tk->symbol ? tk->symbol : "unknown";
95}
96
97static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk)
98{
99 return tk->rp.kp.offset;
100}
101
102static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk)
103{
104 return !!(kprobe_gone(&tk->rp.kp));
105}
106
107static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk,
108 struct module *mod)
109{
110 int len = strlen(mod->name);
111 const char *name = trace_kprobe_symbol(tk);
112 return strncmp(mod->name, name, len) == 0 && name[len] == ':';
113}
114
115static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
116{
117 char *p;
118 bool ret;
119
120 if (!tk->symbol)
121 return false;
122 p = strchr(tk->symbol, ':');
123 if (!p)
124 return true;
125 *p = '\0';
126 mutex_lock(&module_mutex);
127 ret = !!find_module(tk->symbol);
128 mutex_unlock(&module_mutex);
129 *p = ':';
130
131 return ret;
132}
133
134static bool trace_kprobe_is_busy(struct dyn_event *ev)
135{
136 struct trace_kprobe *tk = to_trace_kprobe(ev);
137
138 return trace_probe_is_enabled(&tk->tp);
139}
140
141static bool trace_kprobe_match_command_head(struct trace_kprobe *tk,
142 int argc, const char **argv)
143{
144 char buf[MAX_ARGSTR_LEN + 1];
145
146 if (!argc)
147 return true;
148
149 if (!tk->symbol)
150 snprintf(buf, sizeof(buf), "0x%p", tk->rp.kp.addr);
151 else if (tk->rp.kp.offset)
152 snprintf(buf, sizeof(buf), "%s+%u",
153 trace_kprobe_symbol(tk), tk->rp.kp.offset);
154 else
155 snprintf(buf, sizeof(buf), "%s", trace_kprobe_symbol(tk));
156 if (strcmp(buf, argv[0]))
157 return false;
158 argc--; argv++;
159
160 return trace_probe_match_command_args(&tk->tp, argc, argv);
161}
162
163static bool trace_kprobe_match(const char *system, const char *event,
164 int argc, const char **argv, struct dyn_event *ev)
165{
166 struct trace_kprobe *tk = to_trace_kprobe(ev);
167
168 return strcmp(trace_probe_name(&tk->tp), event) == 0 &&
169 (!system || strcmp(trace_probe_group_name(&tk->tp), system) == 0) &&
170 trace_kprobe_match_command_head(tk, argc, argv);
171}
172
173static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk)
174{
175 unsigned long nhit = 0;
176 int cpu;
177
178 for_each_possible_cpu(cpu)
179 nhit += *per_cpu_ptr(tk->nhit, cpu);
180
181 return nhit;
182}
183
184static nokprobe_inline bool trace_kprobe_is_registered(struct trace_kprobe *tk)
185{
186 return !(list_empty(&tk->rp.kp.list) &&
187 hlist_unhashed(&tk->rp.kp.hlist));
188}
189
190/* Return 0 if it fails to find the symbol address */
191static nokprobe_inline
192unsigned long trace_kprobe_address(struct trace_kprobe *tk)
193{
194 unsigned long addr;
195
196 if (tk->symbol) {
197 addr = (unsigned long)
198 kallsyms_lookup_name(trace_kprobe_symbol(tk));
199 if (addr)
200 addr += tk->rp.kp.offset;
201 } else {
202 addr = (unsigned long)tk->rp.kp.addr;
203 }
204 return addr;
205}
206
207static nokprobe_inline struct trace_kprobe *
208trace_kprobe_primary_from_call(struct trace_event_call *call)
209{
210 struct trace_probe *tp;
211
212 tp = trace_probe_primary_from_call(call);
213 if (WARN_ON_ONCE(!tp))
214 return NULL;
215
216 return container_of(tp, struct trace_kprobe, tp);
217}
218
219bool trace_kprobe_on_func_entry(struct trace_event_call *call)
220{
221 struct trace_kprobe *tk = trace_kprobe_primary_from_call(call);
222
223 return tk ? kprobe_on_func_entry(tk->rp.kp.addr,
224 tk->rp.kp.addr ? NULL : tk->rp.kp.symbol_name,
225 tk->rp.kp.addr ? 0 : tk->rp.kp.offset) : false;
226}
227
228bool trace_kprobe_error_injectable(struct trace_event_call *call)
229{
230 struct trace_kprobe *tk = trace_kprobe_primary_from_call(call);
231
232 return tk ? within_error_injection_list(trace_kprobe_address(tk)) :
233 false;
234}
235
236static int register_kprobe_event(struct trace_kprobe *tk);
237static int unregister_kprobe_event(struct trace_kprobe *tk);
238
239static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
240static int kretprobe_dispatcher(struct kretprobe_instance *ri,
241 struct pt_regs *regs);
242
243static void free_trace_kprobe(struct trace_kprobe *tk)
244{
245 if (tk) {
246 trace_probe_cleanup(&tk->tp);
247 kfree(tk->symbol);
248 free_percpu(tk->nhit);
249 kfree(tk);
250 }
251}
252
253/*
254 * Allocate new trace_probe and initialize it (including kprobes).
255 */
256static struct trace_kprobe *alloc_trace_kprobe(const char *group,
257 const char *event,
258 void *addr,
259 const char *symbol,
260 unsigned long offs,
261 int maxactive,
262 int nargs, bool is_return)
263{
264 struct trace_kprobe *tk;
265 int ret = -ENOMEM;
266
267 tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL);
268 if (!tk)
269 return ERR_PTR(ret);
270
271 tk->nhit = alloc_percpu(unsigned long);
272 if (!tk->nhit)
273 goto error;
274
275 if (symbol) {
276 tk->symbol = kstrdup(symbol, GFP_KERNEL);
277 if (!tk->symbol)
278 goto error;
279 tk->rp.kp.symbol_name = tk->symbol;
280 tk->rp.kp.offset = offs;
281 } else
282 tk->rp.kp.addr = addr;
283
284 if (is_return)
285 tk->rp.handler = kretprobe_dispatcher;
286 else
287 tk->rp.kp.pre_handler = kprobe_dispatcher;
288
289 tk->rp.maxactive = maxactive;
290 INIT_HLIST_NODE(&tk->rp.kp.hlist);
291 INIT_LIST_HEAD(&tk->rp.kp.list);
292
293 ret = trace_probe_init(&tk->tp, event, group);
294 if (ret < 0)
295 goto error;
296
297 dyn_event_init(&tk->devent, &trace_kprobe_ops);
298 return tk;
299error:
300 free_trace_kprobe(tk);
301 return ERR_PTR(ret);
302}
303
304static struct trace_kprobe *find_trace_kprobe(const char *event,
305 const char *group)
306{
307 struct dyn_event *pos;
308 struct trace_kprobe *tk;
309
310 for_each_trace_kprobe(tk, pos)
311 if (strcmp(trace_probe_name(&tk->tp), event) == 0 &&
312 strcmp(trace_probe_group_name(&tk->tp), group) == 0)
313 return tk;
314 return NULL;
315}
316
317static inline int __enable_trace_kprobe(struct trace_kprobe *tk)
318{
319 int ret = 0;
320
321 if (trace_kprobe_is_registered(tk) && !trace_kprobe_has_gone(tk)) {
322 if (trace_kprobe_is_return(tk))
323 ret = enable_kretprobe(&tk->rp);
324 else
325 ret = enable_kprobe(&tk->rp.kp);
326 }
327
328 return ret;
329}
330
331static void __disable_trace_kprobe(struct trace_probe *tp)
332{
333 struct trace_probe *pos;
334 struct trace_kprobe *tk;
335
336 list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
337 tk = container_of(pos, struct trace_kprobe, tp);
338 if (!trace_kprobe_is_registered(tk))
339 continue;
340 if (trace_kprobe_is_return(tk))
341 disable_kretprobe(&tk->rp);
342 else
343 disable_kprobe(&tk->rp.kp);
344 }
345}
346
347/*
348 * Enable trace_probe
349 * if the file is NULL, enable "perf" handler, or enable "trace" handler.
350 */
351static int enable_trace_kprobe(struct trace_event_call *call,
352 struct trace_event_file *file)
353{
354 struct trace_probe *pos, *tp;
355 struct trace_kprobe *tk;
356 bool enabled;
357 int ret = 0;
358
359 tp = trace_probe_primary_from_call(call);
360 if (WARN_ON_ONCE(!tp))
361 return -ENODEV;
362 enabled = trace_probe_is_enabled(tp);
363
364 /* This also changes "enabled" state */
365 if (file) {
366 ret = trace_probe_add_file(tp, file);
367 if (ret)
368 return ret;
369 } else
370 trace_probe_set_flag(tp, TP_FLAG_PROFILE);
371
372 if (enabled)
373 return 0;
374
375 list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
376 tk = container_of(pos, struct trace_kprobe, tp);
377 if (trace_kprobe_has_gone(tk))
378 continue;
379 ret = __enable_trace_kprobe(tk);
380 if (ret)
381 break;
382 enabled = true;
383 }
384
385 if (ret) {
386 /* Failed to enable one of them. Roll back all */
387 if (enabled)
388 __disable_trace_kprobe(tp);
389 if (file)
390 trace_probe_remove_file(tp, file);
391 else
392 trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
393 }
394
395 return ret;
396}
397
398/*
399 * Disable trace_probe
400 * if the file is NULL, disable "perf" handler, or disable "trace" handler.
401 */
402static int disable_trace_kprobe(struct trace_event_call *call,
403 struct trace_event_file *file)
404{
405 struct trace_probe *tp;
406
407 tp = trace_probe_primary_from_call(call);
408 if (WARN_ON_ONCE(!tp))
409 return -ENODEV;
410
411 if (file) {
412 if (!trace_probe_get_file_link(tp, file))
413 return -ENOENT;
414 if (!trace_probe_has_single_file(tp))
415 goto out;
416 trace_probe_clear_flag(tp, TP_FLAG_TRACE);
417 } else
418 trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
419
420 if (!trace_probe_is_enabled(tp))
421 __disable_trace_kprobe(tp);
422
423 out:
424 if (file)
425 /*
426 * Synchronization is done in below function. For perf event,
427 * file == NULL and perf_trace_event_unreg() calls
428 * tracepoint_synchronize_unregister() to ensure synchronize
429 * event. We don't need to care about it.
430 */
431 trace_probe_remove_file(tp, file);
432
433 return 0;
434}
435
436#if defined(CONFIG_KPROBES_ON_FTRACE) && \
437 !defined(CONFIG_KPROBE_EVENTS_ON_NOTRACE)
438static bool within_notrace_func(struct trace_kprobe *tk)
439{
440 unsigned long offset, size, addr;
441
442 addr = trace_kprobe_address(tk);
443 if (!addr || !kallsyms_lookup_size_offset(addr, &size, &offset))
444 return false;
445
446 /* Get the entry address of the target function */
447 addr -= offset;
448
449 /*
450 * Since ftrace_location_range() does inclusive range check, we need
451 * to subtract 1 byte from the end address.
452 */
453 return !ftrace_location_range(addr, addr + size - 1);
454}
455#else
456#define within_notrace_func(tk) (false)
457#endif
458
459/* Internal register function - just handle k*probes and flags */
460static int __register_trace_kprobe(struct trace_kprobe *tk)
461{
462 int i, ret;
463
464 ret = security_locked_down(LOCKDOWN_KPROBES);
465 if (ret)
466 return ret;
467
468 if (trace_kprobe_is_registered(tk))
469 return -EINVAL;
470
471 if (within_notrace_func(tk)) {
472 pr_warn("Could not probe notrace function %s\n",
473 trace_kprobe_symbol(tk));
474 return -EINVAL;
475 }
476
477 for (i = 0; i < tk->tp.nr_args; i++) {
478 ret = traceprobe_update_arg(&tk->tp.args[i]);
479 if (ret)
480 return ret;
481 }
482
483 /* Set/clear disabled flag according to tp->flag */
484 if (trace_probe_is_enabled(&tk->tp))
485 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
486 else
487 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
488
489 if (trace_kprobe_is_return(tk))
490 ret = register_kretprobe(&tk->rp);
491 else
492 ret = register_kprobe(&tk->rp.kp);
493
494 return ret;
495}
496
497/* Internal unregister function - just handle k*probes and flags */
498static void __unregister_trace_kprobe(struct trace_kprobe *tk)
499{
500 if (trace_kprobe_is_registered(tk)) {
501 if (trace_kprobe_is_return(tk))
502 unregister_kretprobe(&tk->rp);
503 else
504 unregister_kprobe(&tk->rp.kp);
505 /* Cleanup kprobe for reuse and mark it unregistered */
506 INIT_HLIST_NODE(&tk->rp.kp.hlist);
507 INIT_LIST_HEAD(&tk->rp.kp.list);
508 if (tk->rp.kp.symbol_name)
509 tk->rp.kp.addr = NULL;
510 }
511}
512
513/* Unregister a trace_probe and probe_event */
514static int unregister_trace_kprobe(struct trace_kprobe *tk)
515{
516 /* If other probes are on the event, just unregister kprobe */
517 if (trace_probe_has_sibling(&tk->tp))
518 goto unreg;
519
520 /* Enabled event can not be unregistered */
521 if (trace_probe_is_enabled(&tk->tp))
522 return -EBUSY;
523
524 /* Will fail if probe is being used by ftrace or perf */
525 if (unregister_kprobe_event(tk))
526 return -EBUSY;
527
528unreg:
529 __unregister_trace_kprobe(tk);
530 dyn_event_remove(&tk->devent);
531 trace_probe_unlink(&tk->tp);
532
533 return 0;
534}
535
536static bool trace_kprobe_has_same_kprobe(struct trace_kprobe *orig,
537 struct trace_kprobe *comp)
538{
539 struct trace_probe_event *tpe = orig->tp.event;
540 struct trace_probe *pos;
541 int i;
542
543 list_for_each_entry(pos, &tpe->probes, list) {
544 orig = container_of(pos, struct trace_kprobe, tp);
545 if (strcmp(trace_kprobe_symbol(orig),
546 trace_kprobe_symbol(comp)) ||
547 trace_kprobe_offset(orig) != trace_kprobe_offset(comp))
548 continue;
549
550 /*
551 * trace_probe_compare_arg_type() ensured that nr_args and
552 * each argument name and type are same. Let's compare comm.
553 */
554 for (i = 0; i < orig->tp.nr_args; i++) {
555 if (strcmp(orig->tp.args[i].comm,
556 comp->tp.args[i].comm))
557 break;
558 }
559
560 if (i == orig->tp.nr_args)
561 return true;
562 }
563
564 return false;
565}
566
567static int append_trace_kprobe(struct trace_kprobe *tk, struct trace_kprobe *to)
568{
569 int ret;
570
571 ret = trace_probe_compare_arg_type(&tk->tp, &to->tp);
572 if (ret) {
573 /* Note that argument starts index = 2 */
574 trace_probe_log_set_index(ret + 1);
575 trace_probe_log_err(0, DIFF_ARG_TYPE);
576 return -EEXIST;
577 }
578 if (trace_kprobe_has_same_kprobe(to, tk)) {
579 trace_probe_log_set_index(0);
580 trace_probe_log_err(0, SAME_PROBE);
581 return -EEXIST;
582 }
583
584 /* Append to existing event */
585 ret = trace_probe_append(&tk->tp, &to->tp);
586 if (ret)
587 return ret;
588
589 /* Register k*probe */
590 ret = __register_trace_kprobe(tk);
591 if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
592 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
593 ret = 0;
594 }
595
596 if (ret)
597 trace_probe_unlink(&tk->tp);
598 else
599 dyn_event_add(&tk->devent);
600
601 return ret;
602}
603
604/* Register a trace_probe and probe_event */
605static int register_trace_kprobe(struct trace_kprobe *tk)
606{
607 struct trace_kprobe *old_tk;
608 int ret;
609
610 mutex_lock(&event_mutex);
611
612 old_tk = find_trace_kprobe(trace_probe_name(&tk->tp),
613 trace_probe_group_name(&tk->tp));
614 if (old_tk) {
615 if (trace_kprobe_is_return(tk) != trace_kprobe_is_return(old_tk)) {
616 trace_probe_log_set_index(0);
617 trace_probe_log_err(0, DIFF_PROBE_TYPE);
618 ret = -EEXIST;
619 } else {
620 ret = append_trace_kprobe(tk, old_tk);
621 }
622 goto end;
623 }
624
625 /* Register new event */
626 ret = register_kprobe_event(tk);
627 if (ret) {
628 pr_warn("Failed to register probe event(%d)\n", ret);
629 goto end;
630 }
631
632 /* Register k*probe */
633 ret = __register_trace_kprobe(tk);
634 if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
635 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
636 ret = 0;
637 }
638
639 if (ret < 0)
640 unregister_kprobe_event(tk);
641 else
642 dyn_event_add(&tk->devent);
643
644end:
645 mutex_unlock(&event_mutex);
646 return ret;
647}
648
649/* Module notifier call back, checking event on the module */
650static int trace_kprobe_module_callback(struct notifier_block *nb,
651 unsigned long val, void *data)
652{
653 struct module *mod = data;
654 struct dyn_event *pos;
655 struct trace_kprobe *tk;
656 int ret;
657
658 if (val != MODULE_STATE_COMING)
659 return NOTIFY_DONE;
660
661 /* Update probes on coming module */
662 mutex_lock(&event_mutex);
663 for_each_trace_kprobe(tk, pos) {
664 if (trace_kprobe_within_module(tk, mod)) {
665 /* Don't need to check busy - this should have gone. */
666 __unregister_trace_kprobe(tk);
667 ret = __register_trace_kprobe(tk);
668 if (ret)
669 pr_warn("Failed to re-register probe %s on %s: %d\n",
670 trace_probe_name(&tk->tp),
671 mod->name, ret);
672 }
673 }
674 mutex_unlock(&event_mutex);
675
676 return NOTIFY_DONE;
677}
678
679static struct notifier_block trace_kprobe_module_nb = {
680 .notifier_call = trace_kprobe_module_callback,
681 .priority = 1 /* Invoked after kprobe module callback */
682};
683
684/* Convert certain expected symbols into '_' when generating event names */
685static inline void sanitize_event_name(char *name)
686{
687 while (*name++ != '\0')
688 if (*name == ':' || *name == '.')
689 *name = '_';
690}
691
692static int trace_kprobe_create(int argc, const char *argv[])
693{
694 /*
695 * Argument syntax:
696 * - Add kprobe:
697 * p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
698 * - Add kretprobe:
699 * r[MAXACTIVE][:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
700 * Fetch args:
701 * $retval : fetch return value
702 * $stack : fetch stack address
703 * $stackN : fetch Nth of stack (N:0-)
704 * $comm : fetch current task comm
705 * @ADDR : fetch memory at ADDR (ADDR should be in kernel)
706 * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
707 * %REG : fetch register REG
708 * Dereferencing memory fetch:
709 * +|-offs(ARG) : fetch memory at ARG +|- offs address.
710 * Alias name of args:
711 * NAME=FETCHARG : set NAME as alias of FETCHARG.
712 * Type of args:
713 * FETCHARG:TYPE : use TYPE instead of unsigned long.
714 */
715 struct trace_kprobe *tk = NULL;
716 int i, len, ret = 0;
717 bool is_return = false;
718 char *symbol = NULL, *tmp = NULL;
719 const char *event = NULL, *group = KPROBE_EVENT_SYSTEM;
720 int maxactive = 0;
721 long offset = 0;
722 void *addr = NULL;
723 char buf[MAX_EVENT_NAME_LEN];
724 unsigned int flags = TPARG_FL_KERNEL;
725
726 switch (argv[0][0]) {
727 case 'r':
728 is_return = true;
729 flags |= TPARG_FL_RETURN;
730 break;
731 case 'p':
732 break;
733 default:
734 return -ECANCELED;
735 }
736 if (argc < 2)
737 return -ECANCELED;
738
739 trace_probe_log_init("trace_kprobe", argc, argv);
740
741 event = strchr(&argv[0][1], ':');
742 if (event)
743 event++;
744
745 if (isdigit(argv[0][1])) {
746 if (!is_return) {
747 trace_probe_log_err(1, MAXACT_NO_KPROBE);
748 goto parse_error;
749 }
750 if (event)
751 len = event - &argv[0][1] - 1;
752 else
753 len = strlen(&argv[0][1]);
754 if (len > MAX_EVENT_NAME_LEN - 1) {
755 trace_probe_log_err(1, BAD_MAXACT);
756 goto parse_error;
757 }
758 memcpy(buf, &argv[0][1], len);
759 buf[len] = '\0';
760 ret = kstrtouint(buf, 0, &maxactive);
761 if (ret || !maxactive) {
762 trace_probe_log_err(1, BAD_MAXACT);
763 goto parse_error;
764 }
765 /* kretprobes instances are iterated over via a list. The
766 * maximum should stay reasonable.
767 */
768 if (maxactive > KRETPROBE_MAXACTIVE_MAX) {
769 trace_probe_log_err(1, MAXACT_TOO_BIG);
770 goto parse_error;
771 }
772 }
773
774 /* try to parse an address. if that fails, try to read the
775 * input as a symbol. */
776 if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
777 trace_probe_log_set_index(1);
778 /* Check whether uprobe event specified */
779 if (strchr(argv[1], '/') && strchr(argv[1], ':')) {
780 ret = -ECANCELED;
781 goto error;
782 }
783 /* a symbol specified */
784 symbol = kstrdup(argv[1], GFP_KERNEL);
785 if (!symbol)
786 return -ENOMEM;
787 /* TODO: support .init module functions */
788 ret = traceprobe_split_symbol_offset(symbol, &offset);
789 if (ret || offset < 0 || offset > UINT_MAX) {
790 trace_probe_log_err(0, BAD_PROBE_ADDR);
791 goto parse_error;
792 }
793 if (kprobe_on_func_entry(NULL, symbol, offset))
794 flags |= TPARG_FL_FENTRY;
795 if (offset && is_return && !(flags & TPARG_FL_FENTRY)) {
796 trace_probe_log_err(0, BAD_RETPROBE);
797 goto parse_error;
798 }
799 }
800
801 trace_probe_log_set_index(0);
802 if (event) {
803 ret = traceprobe_parse_event_name(&event, &group, buf,
804 event - argv[0]);
805 if (ret)
806 goto parse_error;
807 } else {
808 /* Make a new event name */
809 if (symbol)
810 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
811 is_return ? 'r' : 'p', symbol, offset);
812 else
813 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
814 is_return ? 'r' : 'p', addr);
815 sanitize_event_name(buf);
816 event = buf;
817 }
818
819 /* setup a probe */
820 tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
821 argc - 2, is_return);
822 if (IS_ERR(tk)) {
823 ret = PTR_ERR(tk);
824 /* This must return -ENOMEM, else there is a bug */
825 WARN_ON_ONCE(ret != -ENOMEM);
826 goto out; /* We know tk is not allocated */
827 }
828 argc -= 2; argv += 2;
829
830 /* parse arguments */
831 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
832 tmp = kstrdup(argv[i], GFP_KERNEL);
833 if (!tmp) {
834 ret = -ENOMEM;
835 goto error;
836 }
837
838 trace_probe_log_set_index(i + 2);
839 ret = traceprobe_parse_probe_arg(&tk->tp, i, tmp, flags);
840 kfree(tmp);
841 if (ret)
842 goto error; /* This can be -ENOMEM */
843 }
844
845 ret = traceprobe_set_print_fmt(&tk->tp, is_return);
846 if (ret < 0)
847 goto error;
848
849 ret = register_trace_kprobe(tk);
850 if (ret) {
851 trace_probe_log_set_index(1);
852 if (ret == -EILSEQ)
853 trace_probe_log_err(0, BAD_INSN_BNDRY);
854 else if (ret == -ENOENT)
855 trace_probe_log_err(0, BAD_PROBE_ADDR);
856 else if (ret != -ENOMEM && ret != -EEXIST)
857 trace_probe_log_err(0, FAIL_REG_PROBE);
858 goto error;
859 }
860
861out:
862 trace_probe_log_clear();
863 kfree(symbol);
864 return ret;
865
866parse_error:
867 ret = -EINVAL;
868error:
869 free_trace_kprobe(tk);
870 goto out;
871}
872
873static int create_or_delete_trace_kprobe(int argc, char **argv)
874{
875 int ret;
876
877 if (argv[0][0] == '-')
878 return dyn_event_release(argc, argv, &trace_kprobe_ops);
879
880 ret = trace_kprobe_create(argc, (const char **)argv);
881 return ret == -ECANCELED ? -EINVAL : ret;
882}
883
884static int trace_kprobe_release(struct dyn_event *ev)
885{
886 struct trace_kprobe *tk = to_trace_kprobe(ev);
887 int ret = unregister_trace_kprobe(tk);
888
889 if (!ret)
890 free_trace_kprobe(tk);
891 return ret;
892}
893
894static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev)
895{
896 struct trace_kprobe *tk = to_trace_kprobe(ev);
897 int i;
898
899 seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
900 seq_printf(m, ":%s/%s", trace_probe_group_name(&tk->tp),
901 trace_probe_name(&tk->tp));
902
903 if (!tk->symbol)
904 seq_printf(m, " 0x%p", tk->rp.kp.addr);
905 else if (tk->rp.kp.offset)
906 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
907 tk->rp.kp.offset);
908 else
909 seq_printf(m, " %s", trace_kprobe_symbol(tk));
910
911 for (i = 0; i < tk->tp.nr_args; i++)
912 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
913 seq_putc(m, '\n');
914
915 return 0;
916}
917
918static int probes_seq_show(struct seq_file *m, void *v)
919{
920 struct dyn_event *ev = v;
921
922 if (!is_trace_kprobe(ev))
923 return 0;
924
925 return trace_kprobe_show(m, ev);
926}
927
928static const struct seq_operations probes_seq_op = {
929 .start = dyn_event_seq_start,
930 .next = dyn_event_seq_next,
931 .stop = dyn_event_seq_stop,
932 .show = probes_seq_show
933};
934
935static int probes_open(struct inode *inode, struct file *file)
936{
937 int ret;
938
939 ret = security_locked_down(LOCKDOWN_TRACEFS);
940 if (ret)
941 return ret;
942
943 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
944 ret = dyn_events_release_all(&trace_kprobe_ops);
945 if (ret < 0)
946 return ret;
947 }
948
949 return seq_open(file, &probes_seq_op);
950}
951
952static ssize_t probes_write(struct file *file, const char __user *buffer,
953 size_t count, loff_t *ppos)
954{
955 return trace_parse_run_command(file, buffer, count, ppos,
956 create_or_delete_trace_kprobe);
957}
958
959static const struct file_operations kprobe_events_ops = {
960 .owner = THIS_MODULE,
961 .open = probes_open,
962 .read = seq_read,
963 .llseek = seq_lseek,
964 .release = seq_release,
965 .write = probes_write,
966};
967
968/* Probes profiling interfaces */
969static int probes_profile_seq_show(struct seq_file *m, void *v)
970{
971 struct dyn_event *ev = v;
972 struct trace_kprobe *tk;
973
974 if (!is_trace_kprobe(ev))
975 return 0;
976
977 tk = to_trace_kprobe(ev);
978 seq_printf(m, " %-44s %15lu %15lu\n",
979 trace_probe_name(&tk->tp),
980 trace_kprobe_nhit(tk),
981 tk->rp.kp.nmissed);
982
983 return 0;
984}
985
986static const struct seq_operations profile_seq_op = {
987 .start = dyn_event_seq_start,
988 .next = dyn_event_seq_next,
989 .stop = dyn_event_seq_stop,
990 .show = probes_profile_seq_show
991};
992
993static int profile_open(struct inode *inode, struct file *file)
994{
995 int ret;
996
997 ret = security_locked_down(LOCKDOWN_TRACEFS);
998 if (ret)
999 return ret;
1000
1001 return seq_open(file, &profile_seq_op);
1002}
1003
1004static const struct file_operations kprobe_profile_ops = {
1005 .owner = THIS_MODULE,
1006 .open = profile_open,
1007 .read = seq_read,
1008 .llseek = seq_lseek,
1009 .release = seq_release,
1010};
1011
1012/* Kprobe specific fetch functions */
1013
1014/* Return the length of string -- including null terminal byte */
1015static nokprobe_inline int
1016fetch_store_strlen(unsigned long addr)
1017{
1018 int ret, len = 0;
1019 u8 c;
1020
1021 do {
1022 ret = probe_kernel_read(&c, (u8 *)addr + len, 1);
1023 len++;
1024 } while (c && ret == 0 && len < MAX_STRING_SIZE);
1025
1026 return (ret < 0) ? ret : len;
1027}
1028
1029/* Return the length of string -- including null terminal byte */
1030static nokprobe_inline int
1031fetch_store_strlen_user(unsigned long addr)
1032{
1033 const void __user *uaddr = (__force const void __user *)addr;
1034
1035 return strnlen_unsafe_user(uaddr, MAX_STRING_SIZE);
1036}
1037
1038/*
1039 * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
1040 * length and relative data location.
1041 */
1042static nokprobe_inline int
1043fetch_store_string(unsigned long addr, void *dest, void *base)
1044{
1045 int maxlen = get_loc_len(*(u32 *)dest);
1046 void *__dest;
1047 long ret;
1048
1049 if (unlikely(!maxlen))
1050 return -ENOMEM;
1051
1052 __dest = get_loc_data(dest, base);
1053
1054 /*
1055 * Try to get string again, since the string can be changed while
1056 * probing.
1057 */
1058 ret = strncpy_from_unsafe(__dest, (void *)addr, maxlen);
1059 if (ret >= 0)
1060 *(u32 *)dest = make_data_loc(ret, __dest - base);
1061
1062 return ret;
1063}
1064
1065/*
1066 * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf
1067 * with max length and relative data location.
1068 */
1069static nokprobe_inline int
1070fetch_store_string_user(unsigned long addr, void *dest, void *base)
1071{
1072 const void __user *uaddr = (__force const void __user *)addr;
1073 int maxlen = get_loc_len(*(u32 *)dest);
1074 void *__dest;
1075 long ret;
1076
1077 if (unlikely(!maxlen))
1078 return -ENOMEM;
1079
1080 __dest = get_loc_data(dest, base);
1081
1082 ret = strncpy_from_unsafe_user(__dest, uaddr, maxlen);
1083 if (ret >= 0)
1084 *(u32 *)dest = make_data_loc(ret, __dest - base);
1085
1086 return ret;
1087}
1088
1089static nokprobe_inline int
1090probe_mem_read(void *dest, void *src, size_t size)
1091{
1092 return probe_kernel_read(dest, src, size);
1093}
1094
1095static nokprobe_inline int
1096probe_mem_read_user(void *dest, void *src, size_t size)
1097{
1098 const void __user *uaddr = (__force const void __user *)src;
1099
1100 return probe_user_read(dest, uaddr, size);
1101}
1102
1103/* Note that we don't verify it, since the code does not come from user space */
1104static int
1105process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,
1106 void *base)
1107{
1108 unsigned long val;
1109
1110retry:
1111 /* 1st stage: get value from context */
1112 switch (code->op) {
1113 case FETCH_OP_REG:
1114 val = regs_get_register(regs, code->param);
1115 break;
1116 case FETCH_OP_STACK:
1117 val = regs_get_kernel_stack_nth(regs, code->param);
1118 break;
1119 case FETCH_OP_STACKP:
1120 val = kernel_stack_pointer(regs);
1121 break;
1122 case FETCH_OP_RETVAL:
1123 val = regs_return_value(regs);
1124 break;
1125 case FETCH_OP_IMM:
1126 val = code->immediate;
1127 break;
1128 case FETCH_OP_COMM:
1129 val = (unsigned long)current->comm;
1130 break;
1131 case FETCH_OP_DATA:
1132 val = (unsigned long)code->data;
1133 break;
1134#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
1135 case FETCH_OP_ARG:
1136 val = regs_get_kernel_argument(regs, code->param);
1137 break;
1138#endif
1139 case FETCH_NOP_SYMBOL: /* Ignore a place holder */
1140 code++;
1141 goto retry;
1142 default:
1143 return -EILSEQ;
1144 }
1145 code++;
1146
1147 return process_fetch_insn_bottom(code, val, dest, base);
1148}
1149NOKPROBE_SYMBOL(process_fetch_insn)
1150
1151/* Kprobe handler */
1152static nokprobe_inline void
1153__kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
1154 struct trace_event_file *trace_file)
1155{
1156 struct kprobe_trace_entry_head *entry;
1157 struct ring_buffer_event *event;
1158 struct ring_buffer *buffer;
1159 int size, dsize, pc;
1160 unsigned long irq_flags;
1161 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1162
1163 WARN_ON(call != trace_file->event_call);
1164
1165 if (trace_trigger_soft_disabled(trace_file))
1166 return;
1167
1168 local_save_flags(irq_flags);
1169 pc = preempt_count();
1170
1171 dsize = __get_data_size(&tk->tp, regs);
1172 size = sizeof(*entry) + tk->tp.size + dsize;
1173
1174 event = trace_event_buffer_lock_reserve(&buffer, trace_file,
1175 call->event.type,
1176 size, irq_flags, pc);
1177 if (!event)
1178 return;
1179
1180 entry = ring_buffer_event_data(event);
1181 entry->ip = (unsigned long)tk->rp.kp.addr;
1182 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1183
1184 event_trigger_unlock_commit_regs(trace_file, buffer, event,
1185 entry, irq_flags, pc, regs);
1186}
1187
1188static void
1189kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
1190{
1191 struct event_file_link *link;
1192
1193 trace_probe_for_each_link_rcu(link, &tk->tp)
1194 __kprobe_trace_func(tk, regs, link->file);
1195}
1196NOKPROBE_SYMBOL(kprobe_trace_func);
1197
1198/* Kretprobe handler */
1199static nokprobe_inline void
1200__kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1201 struct pt_regs *regs,
1202 struct trace_event_file *trace_file)
1203{
1204 struct kretprobe_trace_entry_head *entry;
1205 struct ring_buffer_event *event;
1206 struct ring_buffer *buffer;
1207 int size, pc, dsize;
1208 unsigned long irq_flags;
1209 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1210
1211 WARN_ON(call != trace_file->event_call);
1212
1213 if (trace_trigger_soft_disabled(trace_file))
1214 return;
1215
1216 local_save_flags(irq_flags);
1217 pc = preempt_count();
1218
1219 dsize = __get_data_size(&tk->tp, regs);
1220 size = sizeof(*entry) + tk->tp.size + dsize;
1221
1222 event = trace_event_buffer_lock_reserve(&buffer, trace_file,
1223 call->event.type,
1224 size, irq_flags, pc);
1225 if (!event)
1226 return;
1227
1228 entry = ring_buffer_event_data(event);
1229 entry->func = (unsigned long)tk->rp.kp.addr;
1230 entry->ret_ip = (unsigned long)ri->ret_addr;
1231 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1232
1233 event_trigger_unlock_commit_regs(trace_file, buffer, event,
1234 entry, irq_flags, pc, regs);
1235}
1236
1237static void
1238kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1239 struct pt_regs *regs)
1240{
1241 struct event_file_link *link;
1242
1243 trace_probe_for_each_link_rcu(link, &tk->tp)
1244 __kretprobe_trace_func(tk, ri, regs, link->file);
1245}
1246NOKPROBE_SYMBOL(kretprobe_trace_func);
1247
1248/* Event entry printers */
1249static enum print_line_t
1250print_kprobe_event(struct trace_iterator *iter, int flags,
1251 struct trace_event *event)
1252{
1253 struct kprobe_trace_entry_head *field;
1254 struct trace_seq *s = &iter->seq;
1255 struct trace_probe *tp;
1256
1257 field = (struct kprobe_trace_entry_head *)iter->ent;
1258 tp = trace_probe_primary_from_call(
1259 container_of(event, struct trace_event_call, event));
1260 if (WARN_ON_ONCE(!tp))
1261 goto out;
1262
1263 trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1264
1265 if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1266 goto out;
1267
1268 trace_seq_putc(s, ')');
1269
1270 if (print_probe_args(s, tp->args, tp->nr_args,
1271 (u8 *)&field[1], field) < 0)
1272 goto out;
1273
1274 trace_seq_putc(s, '\n');
1275 out:
1276 return trace_handle_return(s);
1277}
1278
1279static enum print_line_t
1280print_kretprobe_event(struct trace_iterator *iter, int flags,
1281 struct trace_event *event)
1282{
1283 struct kretprobe_trace_entry_head *field;
1284 struct trace_seq *s = &iter->seq;
1285 struct trace_probe *tp;
1286
1287 field = (struct kretprobe_trace_entry_head *)iter->ent;
1288 tp = trace_probe_primary_from_call(
1289 container_of(event, struct trace_event_call, event));
1290 if (WARN_ON_ONCE(!tp))
1291 goto out;
1292
1293 trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1294
1295 if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1296 goto out;
1297
1298 trace_seq_puts(s, " <- ");
1299
1300 if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1301 goto out;
1302
1303 trace_seq_putc(s, ')');
1304
1305 if (print_probe_args(s, tp->args, tp->nr_args,
1306 (u8 *)&field[1], field) < 0)
1307 goto out;
1308
1309 trace_seq_putc(s, '\n');
1310
1311 out:
1312 return trace_handle_return(s);
1313}
1314
1315
1316static int kprobe_event_define_fields(struct trace_event_call *event_call)
1317{
1318 int ret;
1319 struct kprobe_trace_entry_head field;
1320 struct trace_probe *tp;
1321
1322 tp = trace_probe_primary_from_call(event_call);
1323 if (WARN_ON_ONCE(!tp))
1324 return -ENOENT;
1325
1326 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1327
1328 return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1329}
1330
1331static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1332{
1333 int ret;
1334 struct kretprobe_trace_entry_head field;
1335 struct trace_probe *tp;
1336
1337 tp = trace_probe_primary_from_call(event_call);
1338 if (WARN_ON_ONCE(!tp))
1339 return -ENOENT;
1340
1341 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1342 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1343
1344 return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1345}
1346
1347#ifdef CONFIG_PERF_EVENTS
1348
1349/* Kprobe profile handler */
1350static int
1351kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1352{
1353 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1354 struct kprobe_trace_entry_head *entry;
1355 struct hlist_head *head;
1356 int size, __size, dsize;
1357 int rctx;
1358
1359 if (bpf_prog_array_valid(call)) {
1360 unsigned long orig_ip = instruction_pointer(regs);
1361 int ret;
1362
1363 ret = trace_call_bpf(call, regs);
1364
1365 /*
1366 * We need to check and see if we modified the pc of the
1367 * pt_regs, and if so return 1 so that we don't do the
1368 * single stepping.
1369 */
1370 if (orig_ip != instruction_pointer(regs))
1371 return 1;
1372 if (!ret)
1373 return 0;
1374 }
1375
1376 head = this_cpu_ptr(call->perf_events);
1377 if (hlist_empty(head))
1378 return 0;
1379
1380 dsize = __get_data_size(&tk->tp, regs);
1381 __size = sizeof(*entry) + tk->tp.size + dsize;
1382 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1383 size -= sizeof(u32);
1384
1385 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1386 if (!entry)
1387 return 0;
1388
1389 entry->ip = (unsigned long)tk->rp.kp.addr;
1390 memset(&entry[1], 0, dsize);
1391 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1392 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1393 head, NULL);
1394 return 0;
1395}
1396NOKPROBE_SYMBOL(kprobe_perf_func);
1397
1398/* Kretprobe profile handler */
1399static void
1400kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1401 struct pt_regs *regs)
1402{
1403 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1404 struct kretprobe_trace_entry_head *entry;
1405 struct hlist_head *head;
1406 int size, __size, dsize;
1407 int rctx;
1408
1409 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1410 return;
1411
1412 head = this_cpu_ptr(call->perf_events);
1413 if (hlist_empty(head))
1414 return;
1415
1416 dsize = __get_data_size(&tk->tp, regs);
1417 __size = sizeof(*entry) + tk->tp.size + dsize;
1418 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1419 size -= sizeof(u32);
1420
1421 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1422 if (!entry)
1423 return;
1424
1425 entry->func = (unsigned long)tk->rp.kp.addr;
1426 entry->ret_ip = (unsigned long)ri->ret_addr;
1427 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1428 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1429 head, NULL);
1430}
1431NOKPROBE_SYMBOL(kretprobe_perf_func);
1432
1433int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type,
1434 const char **symbol, u64 *probe_offset,
1435 u64 *probe_addr, bool perf_type_tracepoint)
1436{
1437 const char *pevent = trace_event_name(event->tp_event);
1438 const char *group = event->tp_event->class->system;
1439 struct trace_kprobe *tk;
1440
1441 if (perf_type_tracepoint)
1442 tk = find_trace_kprobe(pevent, group);
1443 else
1444 tk = event->tp_event->data;
1445 if (!tk)
1446 return -EINVAL;
1447
1448 *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE
1449 : BPF_FD_TYPE_KPROBE;
1450 if (tk->symbol) {
1451 *symbol = tk->symbol;
1452 *probe_offset = tk->rp.kp.offset;
1453 *probe_addr = 0;
1454 } else {
1455 *symbol = NULL;
1456 *probe_offset = 0;
1457 *probe_addr = (unsigned long)tk->rp.kp.addr;
1458 }
1459 return 0;
1460}
1461#endif /* CONFIG_PERF_EVENTS */
1462
1463/*
1464 * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1465 *
1466 * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1467 * lockless, but we can't race with this __init function.
1468 */
1469static int kprobe_register(struct trace_event_call *event,
1470 enum trace_reg type, void *data)
1471{
1472 struct trace_event_file *file = data;
1473
1474 switch (type) {
1475 case TRACE_REG_REGISTER:
1476 return enable_trace_kprobe(event, file);
1477 case TRACE_REG_UNREGISTER:
1478 return disable_trace_kprobe(event, file);
1479
1480#ifdef CONFIG_PERF_EVENTS
1481 case TRACE_REG_PERF_REGISTER:
1482 return enable_trace_kprobe(event, NULL);
1483 case TRACE_REG_PERF_UNREGISTER:
1484 return disable_trace_kprobe(event, NULL);
1485 case TRACE_REG_PERF_OPEN:
1486 case TRACE_REG_PERF_CLOSE:
1487 case TRACE_REG_PERF_ADD:
1488 case TRACE_REG_PERF_DEL:
1489 return 0;
1490#endif
1491 }
1492 return 0;
1493}
1494
1495static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1496{
1497 struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1498 int ret = 0;
1499
1500 raw_cpu_inc(*tk->nhit);
1501
1502 if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1503 kprobe_trace_func(tk, regs);
1504#ifdef CONFIG_PERF_EVENTS
1505 if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1506 ret = kprobe_perf_func(tk, regs);
1507#endif
1508 return ret;
1509}
1510NOKPROBE_SYMBOL(kprobe_dispatcher);
1511
1512static int
1513kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1514{
1515 struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp);
1516
1517 raw_cpu_inc(*tk->nhit);
1518
1519 if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1520 kretprobe_trace_func(tk, ri, regs);
1521#ifdef CONFIG_PERF_EVENTS
1522 if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1523 kretprobe_perf_func(tk, ri, regs);
1524#endif
1525 return 0; /* We don't tweek kernel, so just return 0 */
1526}
1527NOKPROBE_SYMBOL(kretprobe_dispatcher);
1528
1529static struct trace_event_functions kretprobe_funcs = {
1530 .trace = print_kretprobe_event
1531};
1532
1533static struct trace_event_functions kprobe_funcs = {
1534 .trace = print_kprobe_event
1535};
1536
1537static inline void init_trace_event_call(struct trace_kprobe *tk)
1538{
1539 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1540
1541 if (trace_kprobe_is_return(tk)) {
1542 call->event.funcs = &kretprobe_funcs;
1543 call->class->define_fields = kretprobe_event_define_fields;
1544 } else {
1545 call->event.funcs = &kprobe_funcs;
1546 call->class->define_fields = kprobe_event_define_fields;
1547 }
1548
1549 call->flags = TRACE_EVENT_FL_KPROBE;
1550 call->class->reg = kprobe_register;
1551}
1552
1553static int register_kprobe_event(struct trace_kprobe *tk)
1554{
1555 init_trace_event_call(tk);
1556
1557 return trace_probe_register_event_call(&tk->tp);
1558}
1559
1560static int unregister_kprobe_event(struct trace_kprobe *tk)
1561{
1562 return trace_probe_unregister_event_call(&tk->tp);
1563}
1564
1565#ifdef CONFIG_PERF_EVENTS
1566/* create a trace_kprobe, but don't add it to global lists */
1567struct trace_event_call *
1568create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
1569 bool is_return)
1570{
1571 struct trace_kprobe *tk;
1572 int ret;
1573 char *event;
1574
1575 /*
1576 * local trace_kprobes are not added to dyn_event, so they are never
1577 * searched in find_trace_kprobe(). Therefore, there is no concern of
1578 * duplicated name here.
1579 */
1580 event = func ? func : "DUMMY_EVENT";
1581
1582 tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func,
1583 offs, 0 /* maxactive */, 0 /* nargs */,
1584 is_return);
1585
1586 if (IS_ERR(tk)) {
1587 pr_info("Failed to allocate trace_probe.(%d)\n",
1588 (int)PTR_ERR(tk));
1589 return ERR_CAST(tk);
1590 }
1591
1592 init_trace_event_call(tk);
1593
1594 if (traceprobe_set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0) {
1595 ret = -ENOMEM;
1596 goto error;
1597 }
1598
1599 ret = __register_trace_kprobe(tk);
1600 if (ret < 0)
1601 goto error;
1602
1603 return trace_probe_event_call(&tk->tp);
1604error:
1605 free_trace_kprobe(tk);
1606 return ERR_PTR(ret);
1607}
1608
1609void destroy_local_trace_kprobe(struct trace_event_call *event_call)
1610{
1611 struct trace_kprobe *tk;
1612
1613 tk = trace_kprobe_primary_from_call(event_call);
1614 if (unlikely(!tk))
1615 return;
1616
1617 if (trace_probe_is_enabled(&tk->tp)) {
1618 WARN_ON(1);
1619 return;
1620 }
1621
1622 __unregister_trace_kprobe(tk);
1623
1624 free_trace_kprobe(tk);
1625}
1626#endif /* CONFIG_PERF_EVENTS */
1627
1628static __init void enable_boot_kprobe_events(void)
1629{
1630 struct trace_array *tr = top_trace_array();
1631 struct trace_event_file *file;
1632 struct trace_kprobe *tk;
1633 struct dyn_event *pos;
1634
1635 mutex_lock(&event_mutex);
1636 for_each_trace_kprobe(tk, pos) {
1637 list_for_each_entry(file, &tr->events, list)
1638 if (file->event_call == trace_probe_event_call(&tk->tp))
1639 trace_event_enable_disable(file, 1, 0);
1640 }
1641 mutex_unlock(&event_mutex);
1642}
1643
1644static __init void setup_boot_kprobe_events(void)
1645{
1646 char *p, *cmd = kprobe_boot_events_buf;
1647 int ret;
1648
1649 strreplace(kprobe_boot_events_buf, ',', ' ');
1650
1651 while (cmd && *cmd != '\0') {
1652 p = strchr(cmd, ';');
1653 if (p)
1654 *p++ = '\0';
1655
1656 ret = trace_run_command(cmd, create_or_delete_trace_kprobe);
1657 if (ret)
1658 pr_warn("Failed to add event(%d): %s\n", ret, cmd);
1659 else
1660 kprobe_boot_events_enabled = true;
1661
1662 cmd = p;
1663 }
1664
1665 enable_boot_kprobe_events();
1666}
1667
1668/* Make a tracefs interface for controlling probe points */
1669static __init int init_kprobe_trace(void)
1670{
1671 struct dentry *d_tracer;
1672 struct dentry *entry;
1673 int ret;
1674
1675 ret = dyn_event_register(&trace_kprobe_ops);
1676 if (ret)
1677 return ret;
1678
1679 if (register_module_notifier(&trace_kprobe_module_nb))
1680 return -EINVAL;
1681
1682 d_tracer = tracing_init_dentry();
1683 if (IS_ERR(d_tracer))
1684 return 0;
1685
1686 entry = tracefs_create_file("kprobe_events", 0644, d_tracer,
1687 NULL, &kprobe_events_ops);
1688
1689 /* Event list interface */
1690 if (!entry)
1691 pr_warn("Could not create tracefs 'kprobe_events' entry\n");
1692
1693 /* Profile interface */
1694 entry = tracefs_create_file("kprobe_profile", 0444, d_tracer,
1695 NULL, &kprobe_profile_ops);
1696
1697 if (!entry)
1698 pr_warn("Could not create tracefs 'kprobe_profile' entry\n");
1699
1700 setup_boot_kprobe_events();
1701
1702 return 0;
1703}
1704fs_initcall(init_kprobe_trace);
1705
1706
1707#ifdef CONFIG_FTRACE_STARTUP_TEST
1708static __init struct trace_event_file *
1709find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1710{
1711 struct trace_event_file *file;
1712
1713 list_for_each_entry(file, &tr->events, list)
1714 if (file->event_call == trace_probe_event_call(&tk->tp))
1715 return file;
1716
1717 return NULL;
1718}
1719
1720/*
1721 * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1722 * stage, we can do this lockless.
1723 */
1724static __init int kprobe_trace_self_tests_init(void)
1725{
1726 int ret, warn = 0;
1727 int (*target)(int, int, int, int, int, int);
1728 struct trace_kprobe *tk;
1729 struct trace_event_file *file;
1730
1731 if (tracing_is_disabled())
1732 return -ENODEV;
1733
1734 if (kprobe_boot_events_enabled) {
1735 pr_info("Skipping kprobe tests due to kprobe_event on cmdline\n");
1736 return 0;
1737 }
1738
1739 target = kprobe_trace_selftest_target;
1740
1741 pr_info("Testing kprobe tracing: ");
1742
1743 ret = trace_run_command("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)",
1744 create_or_delete_trace_kprobe);
1745 if (WARN_ON_ONCE(ret)) {
1746 pr_warn("error on probing function entry.\n");
1747 warn++;
1748 } else {
1749 /* Enable trace point */
1750 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1751 if (WARN_ON_ONCE(tk == NULL)) {
1752 pr_warn("error on getting new probe.\n");
1753 warn++;
1754 } else {
1755 file = find_trace_probe_file(tk, top_trace_array());
1756 if (WARN_ON_ONCE(file == NULL)) {
1757 pr_warn("error on getting probe file.\n");
1758 warn++;
1759 } else
1760 enable_trace_kprobe(
1761 trace_probe_event_call(&tk->tp), file);
1762 }
1763 }
1764
1765 ret = trace_run_command("r:testprobe2 kprobe_trace_selftest_target $retval",
1766 create_or_delete_trace_kprobe);
1767 if (WARN_ON_ONCE(ret)) {
1768 pr_warn("error on probing function return.\n");
1769 warn++;
1770 } else {
1771 /* Enable trace point */
1772 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1773 if (WARN_ON_ONCE(tk == NULL)) {
1774 pr_warn("error on getting 2nd new probe.\n");
1775 warn++;
1776 } else {
1777 file = find_trace_probe_file(tk, top_trace_array());
1778 if (WARN_ON_ONCE(file == NULL)) {
1779 pr_warn("error on getting probe file.\n");
1780 warn++;
1781 } else
1782 enable_trace_kprobe(
1783 trace_probe_event_call(&tk->tp), file);
1784 }
1785 }
1786
1787 if (warn)
1788 goto end;
1789
1790 ret = target(1, 2, 3, 4, 5, 6);
1791
1792 /*
1793 * Not expecting an error here, the check is only to prevent the
1794 * optimizer from removing the call to target() as otherwise there
1795 * are no side-effects and the call is never performed.
1796 */
1797 if (ret != 21)
1798 warn++;
1799
1800 /* Disable trace points before removing it */
1801 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1802 if (WARN_ON_ONCE(tk == NULL)) {
1803 pr_warn("error on getting test probe.\n");
1804 warn++;
1805 } else {
1806 if (trace_kprobe_nhit(tk) != 1) {
1807 pr_warn("incorrect number of testprobe hits\n");
1808 warn++;
1809 }
1810
1811 file = find_trace_probe_file(tk, top_trace_array());
1812 if (WARN_ON_ONCE(file == NULL)) {
1813 pr_warn("error on getting probe file.\n");
1814 warn++;
1815 } else
1816 disable_trace_kprobe(
1817 trace_probe_event_call(&tk->tp), file);
1818 }
1819
1820 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1821 if (WARN_ON_ONCE(tk == NULL)) {
1822 pr_warn("error on getting 2nd test probe.\n");
1823 warn++;
1824 } else {
1825 if (trace_kprobe_nhit(tk) != 1) {
1826 pr_warn("incorrect number of testprobe2 hits\n");
1827 warn++;
1828 }
1829
1830 file = find_trace_probe_file(tk, top_trace_array());
1831 if (WARN_ON_ONCE(file == NULL)) {
1832 pr_warn("error on getting probe file.\n");
1833 warn++;
1834 } else
1835 disable_trace_kprobe(
1836 trace_probe_event_call(&tk->tp), file);
1837 }
1838
1839 ret = trace_run_command("-:testprobe", create_or_delete_trace_kprobe);
1840 if (WARN_ON_ONCE(ret)) {
1841 pr_warn("error on deleting a probe.\n");
1842 warn++;
1843 }
1844
1845 ret = trace_run_command("-:testprobe2", create_or_delete_trace_kprobe);
1846 if (WARN_ON_ONCE(ret)) {
1847 pr_warn("error on deleting a probe.\n");
1848 warn++;
1849 }
1850
1851end:
1852 ret = dyn_events_release_all(&trace_kprobe_ops);
1853 if (WARN_ON_ONCE(ret)) {
1854 pr_warn("error on cleaning up probes.\n");
1855 warn++;
1856 }
1857 /*
1858 * Wait for the optimizer work to finish. Otherwise it might fiddle
1859 * with probes in already freed __init text.
1860 */
1861 wait_for_kprobe_optimizer();
1862 if (warn)
1863 pr_cont("NG: Some tests are failed. Please check them.\n");
1864 else
1865 pr_cont("OK\n");
1866 return 0;
1867}
1868
1869late_initcall(kprobe_trace_self_tests_init);
1870
1871#endif